Im uploading some video right now... but I can honestly tell you it sounds exactly like a catless setup best I can tell from other videos on YouTube.
However, after watching this again... (
) mine seems slightly tamer with the cat pipes installed...
I can also have a parts manager from BMW of Sterling vouch for me. The guys in the garage there think its the best exhaust they have ever seen come in on an E92 M for service. I hear them pull it in the garage from the showroom. Its amazing to watch people's reaction to this thing. Everyone walks over to the window and peeks in the garage to see what it is. They expect to see a full race car I guess.
It makes you smile every time you start it... The deep sound is such that no microphone on a handheld phone or computer speakers could ever catch it.