In case you haven't seen/heard it, here they are:

GPR: http://www.youtube.com/watch?v=udhbFiBiLck
Leo Vince: http://www.youtube.com/watch?v=Po_S3...eature=related
Akra: http://www.youtube.com/watch?v=SkX6qmDjdOg

I don't know about you guys, but I think all exhaust manufacturers should put a sound file next to their respective pipes on their website, so we know what we are buying, especially because we buy after-market pipes mostly for the sound anyway.