recently purchased a
S4 B7 , and would like input and reviews form owners with milltek , apr, ect... thanks .

From what I've heard, Milltek has usally been pretty good, but its new exhaust line for the B7 S4 isn't up to quailty compared to Neuspeeds. Neuspeeds is also a couple decibels louder than the Milltek one and (in my opinion) is a better made exhaust than the Milteks.
The only problem with getting neuspeeds is that they do NOT come with downpipes while the Milteks do. What I'm doing though is I'm just going to buy the downpipes and attach them on to my neuspeed catbacks to solve the problem.

Well I have a B7 S4 and heres a little vid I made a while ago.
Sorry about the quality, it was done with a camera phone.
http://s16.photobucket.com/albums/b14/justinnam/?action=view&current=s4.flv
Your probably gunna have to put the sound loud.

*note, the second part, it somewhat backfire/cracks because the engine was a bit cold. That was at around 4K RPM

Hope that gives you an idea of what the millitek sounds like.

If you have a v8 just about any exhaust that is bigger will make it sound better.