Installed X-Pipes on E92 M3 sounded insane and revved so much quicker/free-er. I said to myself after hearing that, an E92 M3 with X-pipes is on my want list someday .
I ended up buying this m3 from the previous owner after getting the X pipe on.
It sounded great but the only problem was I'd wake the house up if I left early in the morning!