Here's the most current update on this project
Lets be honest and say that the stock BMW M3 E90 E92 V8 really does not have that much of a growl. Like any car, the first mods are usually wheels, intake, and exhaust. With the M3 already have some decent looks factory, the exhaust is a great option to move to. However, we did it all! To really get that intense V8 sound from the BMW M3, we added the complete Agency Power Exhaust. This includes the Section 1 and Section 2 pipes as well as the rear muffler system with titanium tips. The sound you here in the video below comes from this combination. With this, the V8 M3 wakes up and banging through the gears is completely a new experience. The exhaust is made to fit the BMW M3 E93 E92 vehicle. However when fitted to the E90 M3, the tips will stick out an extra 2 inches which the Vorsteiner carbon rear diffuser cleans up nicely. With the addition of the rest of the Vorsteiner BMW aero upgrade, Brembo Brakes, H&R suspension, and Volk G2 Racing wheels, this project is the ultimate daily driver. However it is 1 step away from the next major upgrade courtesy of VF Engineering and their 620HP supercharger kit!
http://www.youtube.com/watch?v=OsuVsmyBILg