what type of exhaust

[audispeed08]

I have a 2005 B6 A4 1.8t 6spd with APR stage 1+. I am looking for an exhaust that isn't too loud and is pretty quite at the lower RPMs. What do you all think is the best? Should I stay with APR because my car was chipped there or should i do something else?

Also I have a question about exhaust in general. So i've heard that it gives you horse power and improves throttle response. Are both of these true or what the deal? How much Horse power do you think i can gain from exhaust if i already have the chip and fuel injectors from APR.

Thanks