Performance Headers/Exhaust

I am trying to come up with ideas for an exhaust system. I have search all over the internet, including this forum and I am having terrible luck. I know about Super Sprint, Remus ect but they dont offer much, just mufflers and tips from what I can tell. My plan is the do a complete exhaust system from the headers to the tips. If anyone can point me in the direction of any aftermarket companys or build threads from this or other sites I would greatly appreciate it.

Car is a 2001 BMW 740iS