I was wondering what cat-back exhaust puts out the most horsepower without going over 95 DB(a)...

 

I am not sure but I did the Buschur turbo back, and I got 25whp from it and it was at 97dbls. <--- I know this because I was pulled over for noise ordinance restrictions. Bunch of B.s. if you ask me. The cop asked me to rev my engine to full throttle to measure it.
I even got Buschur for my 2nd gen eclipse. I am very happy with results and sound from them.

 

BR all the way

 

Espelir JGT 500, one of few that is 50 state legal meeting 95dbls or lower.