Will putting a cat back exhaust on my 87 GXL make a sound difference or any difference at all? Or do the 2 cats and pre silencer absorb all the sound before the mufflers. I also have intake if that makes any difference.

It'll make a differance, ive got blow out stock mufflers, and there louder than a stock FC, not by a whole hell of alot, but its noticable.

you should notice a difference

Some catback systems will sound different from others. The Racing Beat systems give good power with a quiet tone. Most other systems will give good power, but they will be VERY loud.

How do the Borla's sound?

Robx-7 has a Borla setup, and it's pretty loud, even with a converter.

Ive got a Borla setup, and from the stock exhaust to the Borla catback exhaust system, it got pretty loud.

My friend has a borla set-up and he is using a RB presilencer. It sounds so good. Not raspy or loud. Just a good deep sound. It totally depends on which muffer you go with though as well. Good luck.

yea if u want basey rumble id go with borla but get a presilencer, cuz without it cops get a little annoyed and could lead to then pestering u