$595.00 USD
$595.00 USD




















The Valvetronic Designs Valved Exhaust System for the BMW G29 Z4 M40i is the ultimate upgrade for enthusiasts who demand both performance and versatility. Developed from our extensive R&D on B58-powered platforms—including the Supra and M340i—this system transforms the Z4’s sound and performance, unlocking the true potential of BMW’s celebrated inline-six.
Valves Open: A rich, aggressive tone with crisp throttle response, pronounced turbo spool, and motorsport-inspired overrun.
Valves Closed: A refined, stock-like sound perfect for long cruises or early-morning starts—ideal when you want performance without the attention.
Maximum Flow Design: Single 3.5" midsection transitioning into dual 3" mandrel-bent runs for optimal exhaust scavenging and reduced backpressure.
Balanced Sound Profile: Tuned for a deep, full-bodied note inspired by our acclaimed B58 Supra and M340i systems.
Precision Construction: TIG-welded T304 stainless steel for exceptional durability and corrosion resistance.
2017+ BMW G29 Z4 M40i
Fully mandrel-bent for maximum flow
Precision TIG welds for high strength
Built from T304 stainless steel
Electronic-actuated valves for rapid and reliable operation
11.1 lbs lighter than the factory exhaust
Beautiful tips to complement the Z4’s styling
100% reversible—return to stock at any time
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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.