[quickxotica]

This is well-researched turf, and you'll benefit greatly from talking to folks who've done it a thousand times, like Brian Bodart of M&K. Don't just buy stuff without talking to him (or folks like him) first. The right answer will depend on your goals and your car's other mods (if any).

I have an '85 3.2 that I'm keeping to an OEM+ level of restomods, no more. So, I went with the M&K "active exhaust" catalytic converter swap and the MKM33 1-in-1 out muffler. Throttle response definitely improved by swapping out the original cat to the active one. The MKM33 muffler doesn't drone at all and the combination sounds great -- nice and deep tone but not too loud. You can still hear the characteristic fan whir of an aircooled 911. Brian was very responsive by both phone and text when I had questions. Super happy customer here.