Sounds great! Mine goes on tomorrow! Now I'm excited. Since we are vendors on here my dealership is throwing one on my car for marketing purposes. To be honest though I don't believe that there is any power gains. I think it's just for a more aggressive sound. What I've noticed on the other BMW Performance and M Performance exhausts is that the casing is very close to stock with the internals being different to create the more aggressive sound. When I did my 135 BMW Performance exhaust there was no difference in weight or power just sound.
2013 E92 335i M-Sport/BSM/Black Dakota Leather/Dark Glacier Trim/Steptronic/230's/Premium/Convenience/Premium Sound/Apps/Navigation/Heated Seats/BMW Performance Grills/BMW Performance CF Mirror Caps/BMW Performance CF Splitter/BMW Performance CF Spoiler/BMW Performance Exhaust/Painted Reflectors/15% Tint