SKU: 27186522921

Competition Series Catless Secondary Downpipes 2018-23 M5/M8 S63M Engine

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Ships within 48 hours · Estimated delivery Aug 17 - Aug 22

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Description

Competition Series Catless Secondary Downpipes 2018-23 M5/M8 S63M EngineIntroducing our Competition Series Catless Secondary Downpipes for your twin turbo S63M engine! Fits 2018 23 M5 (F90) & 2018 23 M8 (F92 F93). Key Features: Made in the USA! Manufactured in house. Now available for the 2018 23 BMW F90 M5 & F92 F93 M8 S63M Engines! Does not set off the Check Engine Light (CEL). Higher Max Horsepower Power Curve Higher Initial Torque Curve. Torque curve hits faster and higher and longer. Better throttle response and

Introducing our Competition Series Catless Secondary Downpipes for your twin turbo S63M engine!  Fits 2018-23 M5 (F90) & 2018-23 M8 (F92/F93).

Key Features:

  • Made in the USA!  Manufactured in house.
  • Now available for the 2018-23 BMW F90 M5 & F92/F93 M8 S63M Engines!
  • Does not set off the Check Engine Light (CEL).
  • Higher Max Horsepower Power Curve
  • Higher Initial Torque Curve.  Torque curve hits faster and higher and longer.
  • Better throttle response and faster turbo spool up times.
  • Mandrel Bent 3" piping.  Smooth transition to the exhaust system.
  • 100% Stainless Steel Construction
  • 100% TIG welded for better quality welds
  • Precision CNC machined turbocharger V-Band flange.
  • Mirror polish or brush finish
  • Available with high temperature black thermal coating to reduce underhood temperatures.
  • Retains factory slip on style connection.
  • Compatible with the factory or aftermarket secondary downpipes.
  • Track tested durability.
  • Includes all hardware for complete installation.
  • Limited Lifetime Warranty.

Restrictions in the exhaust system robs horsepower and torque especially on turbocharged cars.  Thus, removing as much exhaust flow restrictions will increase horsepower and torque significantly.  The factory catalytic converter found in the factory downpipe is a big culprit of this and is a major exhaust flow restriction.  The factory catalytic converter is made up of catalyst material formed into "honeycomb" weaves.  Exhaust gas must pass through these tiny "honeycomb" weaves on their way to the exhaust system thus causing a major exhaust flow restriction.  It also causes turbulence after the catalytic converter which causes the exhaust flow to slow down (which increases restriction).  By replacing the factory downpipe/catalytic converter with our Competition Series Catless Downpipe, more power is unleashed!  You will feel the difference instantly. 

Our Competition Series Catless Downpipes is constructed out of 100% 304 grade stainless steel and utilize mandrel bent piping. They are 100% TIG welded by our in-house fabricators and built in the USA.  The factory turbocharger turbine housing utilizes a 3.5" V-Band flange which we have duplicated, and CNC machined cut out of billet 304 stainless steel.  Stainless Steel CNC machined O2 sensor and laser cut brackets are TIG welded using stainless steel rods.  The O2 sensor is positioned at the factory location.  100% bolt on. 

Our downpipes are designed to fit perfectly with either the factory exhaust system or your aftermarket exhaust system.  There are no compatibility issues whatsoever.  The downpipes will come by default with brushed finish.

The BMW M5 (F90) and M8 (F92/F93) has 2 primary catalytic converters and 2 secondary catalytic converters for a total of 4 catalytic converters.  Our Competition Series Catless Secondary Downpipes replace just the secondary section.  You can retain the factory primary catalytic converter or aftermarket primary section.  Will match up to factory or aftermarket exhaust systems.  The secondary downpipes are after the secondary o2 sensor that monitors the catalytic converter so changing it will not set off a check engine light (CEL).

OPF Compatibility (EU & Asia Spec)

European Spec & Asia Spec cars feature the Otto Particulate Filter (OPF) system as part of their emissions equipment.  We now offer downpipes that are compatible with the OPF system and allows you to retain full function of it.  

OPTIONS

Ceramic Thermal Coating - The purpose of ceramic coating downpipes is to keep heat from the exhaust gases inside the downpipe from radiating out. This keeps underhood temperatures lower and less heat absorption by nearby parts/surfaces.  Another added benefit is that by keeping in heat (energy) in the exhaust gases inside the downpipe, exhaust flow velocities stay up, resulting in lower backpressure. The ceramic coating also adds additional corrosion resistance. We utilize the best ceramic coating possible. Our thermal coating can resist up to 2000F of heat. It is available in black only (all the other colors cannot withstand the high levels of heat).

CAUTION: This product is intended for OFF ROAD COMPETITION USE ONLY. Not legal for use on pollution controlled vehicles upon public road/highways. THIS PRODUCT IS FOR SALE FOR ALL 49 STATES EXCLUDING CALIFORNIA.  In addition to vehicle use verification, a Vehicle Compliance Waiver needs to be signed.

THIS ITEM IS NOT FOR SALE, INSTALLATION, OR USE ON LICENSED VEHILES IN THE STATE OF CALIFORNIA. 

The item is for sale for international customers without restriction.

Please contact us at [email protected] or call us at (626) 334-6609

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 27186522921

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4.2 ★★★★★
Based on 19 reviews
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Product Reviews
A
Amazon Customer
Grantham, US
★★★★★ 5
Versatile Room Divider With Easy Assembly and Strong Coverage
Size: 3 Panel 12FT W
I picked up this Siebwin 3-panel folding room divider mainly for privacy and room separation, and overall it works very well. Assembly is very straightforward, and the divider can be set up, taken apart, and stored without much effort. The fabric quality feels good, and the frame construction is stronger and more stable than expected. The support tubes especially feel well built and help keep the divider standing securely. One feature I really liked is the flexibility of the design. The panels can be used together as a complete divider or separated depending on the setup and available space. That makes it much more versatile for different room layouts or temporary privacy needs. The coverage is also very good, and the size matches the manufacturer’s description accurately. The fabric blocks light and background visibility well enough to provide solid privacy without feeling overly heavy. The wider feet also help improve stability compared to thinner folding dividers. Another positive detail is that everything arrived complete with no missing parts or damaged pieces, which made assembly much easier and faster. Compared to cheaper privacy screens, this one feels more durable and easier to customize depending on the situation. In terms of value for the money, it feels like a very practical and worthwhile purchase considering the size, flexibility, and build quality. Overall, a versatile and well-built room divider with easy assembly, strong privacy coverage, stable construction, complete included parts, flexible panel configuration, and excellent everyday functionality.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 27, 2026
F
Fred
Draper, US
★★★★★ 5
Stable, flexible in deployment configuration, creates true privacy and looks great.
Size: 3 Panel 12FT W
This is the second room divider panel I have installed, and there are several features about this one that I like much better than my older one. The fact that there are no gaps and that the material is thicker means you get more privacy or more hiding power, if you wish. My older divider has vertical spaces between each of the panels and the panels are half as wide as the Siebwin panels, so there are many vertical spaces. The Siebwin divider really creates privacy. Another feature that I really appreciate is that the legs are wider and stand off from the floor. On my older one the legs are flat and they're rather awkward to adjust because they create more drag on the floor. The feet on the older one also loosen if you turn them counter clockwise, so adjustments of configuration that require the feet to be moved are more complex. The older divider also must be deployed in a zig-zag fashion because he feet are not as wide, but this new one can be deployed and stable in a straight, an "N" shape or an arc. They are both the same length, but because the older one must be use in a zig-zag deployment it doesn't reach to the length of the new one. The Siebwin divider definitely costs more at $103.48, but it sports several features and advantages over the other brand, so it does a better job and is worth the extra cost.
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Reviewed in the United States on May 25, 2026
C
Computer
Pawtucket, US
★★★★★ 4
Easy to assemble, does the job, material is shiny nylon and shows creases, minor defects, sloppy
Size: 3 Panel 12FT W, Size: 3 Panel 12FT W
The Siebwin room divider is a good idea, and for the price, it mostly delivers on the intended functionality. I ordered the 12 foot, 3-panel version mainly to hide an unfinished basement storage area that had become an eyesore. It works well for that purpose and gives the space a cleaner appearance without spending the kind of money that more decorative dividers or custom partitions cost. If you need something temporary, portable, or mainly functional, this is a viable option. There are a few limitations that became obvious during setup and use. The first thing I noticed was that the weld quality on some of the metal poles is fairly sloppy. Once the cover is installed, you do not really see it, but up close, it does not look especially refined or professional. The blackout material also is not a matte canvas style fabric as I expected. It has more of a shiny nylon appearance, and the creases are fairly visible. Being that it’s more of a nylon, I’d be hesitant to try steaming it to remove the creases. However, the creases do not matter if you are using it in a basement, dorm, or shared room, but for photography, video work, or a professional office setting, the appearance could be disappointing. The fabric is thick enough, though. It blocks visibility well enough, but strong light behind it still shows through to some extent, nothing deal-breaking. Also, my fabric appeared to be slightly defective. The hook and loop strip on one of the bottom sections was off-center and couldn't be totally attached because it was lined up with one of the legs. I originally hoped to use this as a video backdrop, but I will probably end up replacing the fabric with a proper green screen or canvas material while continuing to use the frame itself. For now, it does a good job of covering my basement junk. Assembly was actually easier than I expected and took roughly 15 to 20 minutes. The longer vertical poles are tethered together similarly to tent poles, which made setup straightforward and fairly intuitive. The shorter horizontal pieces slide and snap together to the top and bottom of the vertical assembly. After each section is assembled, the divider panels connect together with metal plates and two knurled screws (at the top and bottom), so no tools are really required. A few screws were difficult to start because paint had gotten into the threads, but once they caught, they tightened down normally. The feet install with similar knurled fasteners and help keep the divider reasonably stable. One thing to watch for during setup is the fabric orientation. There is one arrow indicator in the middle of the fabric to indicate up. However, if you need another indicator, the smaller hook and loop strip goes on the bottom while the longer strip goes on top. I realized mine was upside down right before finishing and had to redo it. I wasn't difficult to redo, despite the defect in mine. The overall design is practical and easy to move around. I do like that the panels can fold and bend into different shapes depending on the space. The widened feet help stability, although when trying to stretch the fabric tight, I noticed the poles sometimes wanted to overlap slightly at the joints. Tightening everything helped somewhat, but it still happened occasionally. The divider feels adequate for normal indoor use, though I would not expect premium durability or luxury-level fit and finish at this price point. The entire device can also be easily disabled and stored in a tote if you need it completely out of the way. It comes with assembly instructions, but even if you didn’t have them, it’s easy to build without them (save a mistake or two). In terms of value, I think the Siebwin divider mostly matches its price. Around $100 gets you a large freestanding partition with decent usability and easy assembly, but there are compromises in materials, appearance, and refinement. The defects are also off-putting, but hopefully you won't have them. Higher-end room dividers can easily cost two or three times more, so some of the tradeoffs are expected. I also noticed cheaper alternatives online, but based on the quality here, I suspect those would probably have even more issues. For practical home use, temporary privacy, hiding storage areas, or separating shared spaces, this is a good option as long as expectations stay realistic.
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Reviewed in the United States on May 18, 2026
T
Trendy Tales
Bozeman, US
★★★★★ 3
Works well but takes up more space than expected
Size: 2 Panel 8FT W, Size: 2 Panel 8FT W
This room divider does the job for creating a little extra privacy and was easy enough to set up. The panels feel decent quality and the wider feet help keep it more stable than some cheaper screens I’ve tried. My only issue is that it takes up a bit more room than I expected, especially with the feet sticking out. It’s still portable and folds away nicely, but definitely measure your space first. Overall it works well for separating a room or blocking off an area temporarily. i wish it came in other colors
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 26, 2026
K
Katrina Rhodes
New York, US
★★★★★ 5
Nice divider, serves it's purpose well!
Size: 3 Panel 12FT W
This room divider worked out very well for what I needed. I wanted a simple way to create a little more privacy and separation in a larger room without doing anything permanent, and this divider was an easy solution. The panels provide good coverage, and the black color gives it a clean, modern appearance that blends in nicely with different décor styles. Assembly was fairly straightforward, and once set up, the wider feet helped keep the divider stable on the floor. I was especially happy with how flexible the panels are to arrange. You can keep it mostly straight, angle it around furniture, or create a more enclosed private space depending on the layout you need. The material allows light to filter through slightly while still offering a noticeable sense of privacy. I’ve used it for separating a workspace area, but it would also work well in bedrooms, apartments, dorms, studios, or shared living spaces. Another plus is that it can be folded and moved without too much effort when you want to change the setup. Overall, this divider delivers a good balance of functionality, portability, and appearance. It’s a practical option for anyone needing temporary room separation without installing permanent walls or curtains.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 26, 2026

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