I know absolutely nothing about exhaust systems,
not my thing, but recently a friend got a 94 camaro with aftermarket exhaust and this thing sounded baaad assss.

i wanted to know for a 91 firebird, wat would be the sickest exhaust system to buy?

 

His same exhaust would fit your car, no problem....But a LT1 will sound slightly different than a L98. And even the LS1 exhaust will bolt up, with few problems. But again....The different engine makes the exhaust sound different.

I have a aftermarket LS1 cat-back on my L98. Sounds good, but doesn't sound like it would, on a LS1.