Can someone tell me the diameter of the Y-Pipe?
and of the Stillen exhaust?

I am also looking to do the entire exhaust system, front to back. Exactly what parts will I change? (Y-pipe, Cat, B-pipe, exhaust?, did I miss something?) I don't want it to be loud, so I am going with a resonator, or is there something better?
Is this process of changing the ENTIRE system better than just doing the Y-pipe? What is the approximate cost that I am looking at for the whole system, and how loud will it be?
I know Stillen is loud, so I am probably gonna go with a different make for quiter ride.

Thank you