$595.00 USD
$595.00 USD






































































The S55 engine in the M2 Competition and M2 CS delivers exceptional performance, but its stock exhaust note leaves much to be desired—buzzy, raspy, and lacking the refined aggression enthusiasts expect. The Valvetronic Designs Equal-Length Valved Cat-Back Exhaust System solves this problem, unlocking the hidden character of the S55 while preserving the excitement and volume owners crave.
This system combines a 2.75-inch equal-length mid-section with an H-pipe and a 3.5-inch axle-back, delivering a smoother, richer tone across the rev range. With valves open, exhaust gases exit freely through the passenger-side tips for maximum presence. With valves closed, gases are routed through our quad-chamber muffler and driver-side tips, offering a quieter, more refined sound—perfect for daily driving.
Direct bolt-on fitment means installation is seamless, mounting to factory points without permanent modifications.
Equal-Length Mid-Section: Balances exhaust pulses for a smoother, more pleasant tone without sacrificing aggression.
H-Pipe Integration: Improves exhaust scavenging for a fuller, richer sound.
Dual Sound Modes: Enjoy raw, motorsport tone (open) or comfortable refinement (closed).
Valves Open: Aggressive, free-flowing tone with improved top-end character.
Valves Closed: Stock-like volume and tone for discreet driving.
Electronic Valve Control: Includes remote controller; OEM valve integration optional.
Materials: T304 stainless steel or Grade 5 titanium.
Weight Savings: –20.9 lb (Stainless) / –47.3 lb (Titanium) compared to OEM.
Craftsmanship: Precision TIG welds, fully mandrel-bent tubing.
Tips: Premium tips available in multiple finishes to match your style.
2018+ BMW F87 M2 Competition
2020 BMW M2 CS
Direct bolt-on installation to OEM mounting points.
100% reversible—return to stock at any time.
Note for S55 Owners: On race or free-flow downpipes, “2k rpm rasp” may be present during low-rpm shifts. For the most refined tone, we recommend high-flow (200 cell) catalytic converters.
2.75" equal-length H-pipe mid-section
3.5" axle-back with quad-chamber muffler
Electronic valve system with controller (OEM integration optional)
All required clamps and hardware
Mid-Section Diameter: 2.75" equal-length with H-pipe
Axle-Back Diameter: 3.5"
Material: T304 stainless steel or Grade 5 titanium
Valves: Electronic, rapid open/close
Weight Savings: –20.9 lb (Stainless) / –47.3 lb (Titanium) vs. OEM
Design: Quad-chamber muffler for refined closed-valve tone
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$595.00 USD
$595.00 USD
This product can expose you to chemicals such as lead and lead compounds, which are known to the State of California to cause cancer or birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov.
For a complete list of chemicals known to cause harm, visit https://www.p65warnings.ca.gov/chemicals.
Under the federal Clean Air Act (42 U.S.C. §7522(a)(3)), it is illegal to manufacture, sell, install, or use any part that defeats or alters a motor vehicle’s emission control system for use on public roads. Unless a product has received an Executive Order (EO) from the California Air Resources Board (CARB), it is not legal for use or installation on any pollution-controlled vehicle driven on public highways.
Some states have CARB-equivalent or independent emissions laws. Customers are responsible for verifying local regulations before purchasing or installing emissions-related products.
All performance, racing, or competition parts sold by this company are intended solely for off-road, closed-course, or competition use on vehicles that are never registered or used on public highways.
Kies Motorsports, LLC sells and markets these products for lawful use only. We do not condone or authorize the use of emission-control defeat devices or any modification that violates the Clean Air Act or state regulations.