i have a 95gt and i would like to if a catback exhaust system would sound louder than just welded in mufflers. thanks

 

I doubt you would notice a difference in sound, but you would get better performance with a catback system from the larger mandrel bent pipes.

 

Would there be a performance benefit from the larger pipes and better muffler even if I stick with the stock H-pipe? In other words, would it be worth it to replace the mufflers only or should I replace everything after the H-pipe?

 

Climb under your car and look at those pipes. if that doesn't convince you nothing will.