The Yonristic Performance Valved Cat-Back Exhaust System for the BMW F8X M3 and M4 was engineered to unlock the true potential of the S55 engine. While the factory exhaust often leaves enthusiasts disappointed with thin, raspy tones, our system transforms the car’s voice into something richer, smoother, and more exotic. By utilizing a 2.75-inch equal-length midsection with an H-style crossover, we balanced exhaust pulses to reduce harshness and create a deeper, fuller resonance across the rev range. The gases then flow through a 3.5-inch axle-back, giving the S55 a clean, linear sound profile that builds into a spine-tingling crescendo at redline — the way a true performance engine should sound.
At the heart of this design is a dual-path valved system that delivers two distinct personalities in one exhaust. With the valves open, the system provides a nearly straight-through flow, maximizing volume, power, and aggression — complete with sharp overrun crackles and an exotic high-pitched edge. With the valves closed, gases are redirected through a multi-chamber performance muffler, which calms the volume and filters out unwanted frequencies, resulting in a refined, comfortable note for daily driving. Thanks to full OEM valve integration, this transformation is instant, controlled seamlessly through factory drive modes or an optional standalone controller.
The build quality of the Yonristic Cat-Back is equally uncompromising. Constructed from either AISI 304 stainless steel or Grade 5 titanium (Ti-6Al-4V), the system offers both durability and performance-driven weight reduction. The titanium variant saves nearly 50 pounds over stock, improving balance, handling, and throttle response. Each piece is crafted with 3D-scanned data and CNC-machined flanges for perfect OEM fitment, while hand TIG welding ensures structural strength and visual artistry. The system is finished with quad 4-inch tips, offered in polished stainless, carbon fiber, black chrome, or burnt titanium, creating a bold aesthetic to match the sound.
More than just an upgrade, the Yonristic Valved Cat-Back is a reimagining of the S55’s true voice. It eliminates the flat, metallic rasp of the factory system and replaces it with a commanding, exotic tone that feels at home both on the street and at the track. It’s the perfect balance of engineering precision, motorsport-inspired sound, and everyday usability, giving the F8X platform the presence it deserves. With this exhaust, your M3 or M4 doesn’t just sound louder — it sounds alive.
