In order to achieve desired sound volume and tone, Dinan felt becoming of the F90 M5 the tubing was enlarged to 83mm (vs 80mm stock) to allow freer flow throughout the entirety of the system. The larger tubing is fed into a muffler that is typical of all Dinan exhaust design and utilizes absorption and reactive technologies designed to improve exhaust flow and reduce backpressure. The combination results in increased power output and a great sporty sound that is civilized when you want it to be, and pleasantly aggressive under hard acceleration. This is partly courtesy of the retained computer-controlled exhaust valves that limit noise during low-speed driving and open fully during high-load conditions to allow free flow and greater sound as the bulk of the gases are bypassing the muffler. Like all Dinan exhausts, our M5 free flow exhaust is engineered to reduce low-RPM drone so the cabin of the vehicle is still intimate and not drowned in an excessively loud tone. With the Dinan exhaust equipped on the M5 you get the best of both worlds; aggressive tone/sound and civility. A combination that we have termed internally as "refined aggression."

Stainless Steel - Polished Tips - F90

• Stock exhaust valve actuators reused and operation of exhaust valve is unchanged so exhaust tone can be adjusted via the M-drive settings
• Computer controlled exhaust valves are retained and limit noise during low speed driving and open fully during high-load conditions
• Twin secondary exhaust valves are a whopping 76mm diameter, making them 30% less restrictive than the OE valves
• Four massive 4" diameter clamp-on, double-walled, polished and laser engraved exhaust tips
• Easy bolt-on installation with included mounting hardware
• Larger diameter piping for increased flow (83mm vs 80mm)
• More Power: + 6 HP @ 6600 RPM, + 5 LB-FT @ 6600 RPM
• 100% 304 stainless steel construction
• Enjoyably louder, sportier sound