engine upgrades

[Bewildered@aol.com]

I realize that this subject has been discussed in the past but I still don't
seem to be clear on the answer so I'll throw it out there again and hopefully
some of you will be able to shed some more light on the subject.
I want to increase the power on my S4 and I had pretty much decided to go
with either the IA or the Hoppen chip. But what exactly is it that is bad
about the TAP upgrades? Also, has anyone tried either the Scorpion cat-back
exhaust from England that TAP sells or the turbo-back system that they have
fabricated here in the States? They claim that either of these will reduce
back pressure more than will the RSR manifold, resulting in quicker turbo
spool up. 
Also, they offer a K24 turbo unit with modified garrett turbine wheels that
is also supposed to spool up quicker than the RSR unit. And finally, how does
the manifold which Ned Ritchie sells compare to the RSR unit?
I hope someone with the knowledge will be kind enough to explain what they
know to the rest of us. Thanks. Also, anyone know of a good Audi garage in
the Cincinnati area?

Bill