My 90sc is getting two new OEM cats down to two glass packs (cherrybombs) with custom bent out the back . Glass packs closer to the cats. I've ran this before ,kinda loud .she is on the hoist right now getting pipes!
The exhaust topic has been mentioned several times. Basically you need a large resonator if you do straight flow rear mufflers, preferably cats too to combat drone, a quieter alternative Is chambered rear mufflers but ensure they are S type chamber. Dual 2.5 is most common. But a 3” mid section and 2.25 will work on most mediums build. The quieter the better, the firing order and V6s makes for a terrible sounding exhaust. Rasp and drone are not in your favor.
I have David Dalke spcial Truebenz (mandrelexhaustsystems) 2.5 true dual aluminumized steel exhaust with X-pipe with resonator long body 4x9 mufflers Magnaflow Mufflers (pn 11256 MagnaFlow 4" X 9" Oval Center/Offset Straight Through Performance Muffler) Magnaflow Cats (pn 94606).