Another vote for the OEM mod. The original thread is still running if you do a quick search. Sounds as good or better than anything you can get shy of 3 grand, for about 300 bucks.
2011.5 LeMans Blue e92 DCT, ZCP, European Delivery. Black Edition Grilles, No Keyhole or Reflectors, Rear Fogs Enabled, Encore Innovation Exhaust, LUX Angel Eyes, 255x285's. "Last of the V-8 Interceptors, a real piece of history..."