I rigged up a decent side-exit exhaust on my previous '89 with a pair of Dynomax mufflers that have the inlet/outlet on the same side (I believe the part number was 37676 ... it's listed in their online catalog). Just bolt the muffs to the flow tubes, then run a 90* elbow on each followed by either a 45* elbow (if you want a slanted-back look) or a long, straight extension (if you want the straight-out look) and you're set. I only spent about $150 total in hardware. You will have to invest in a couple of OEM-style exhaust hangers for the muffs, if you don't have a set you can transfer onto them, already.
As far as sound, I loved 'em - sounded more like that Charger in the movie "Bullitt" than the 'Stang, actually (much deeper tone) - and they didn't drone at all. Ground clearance was good, although I did have them adjusted in such a way that I compromised body-to-exhaust clearance in favor of ground clearance, thus my pipes kept thumping against the floorboards on heavy dips/bumps. Can't offer any definitive answers on subframe connector fitment with the above, although I have seen pics of another member who rigged up something similar solely for the purpose of clearing the heavy-duty rear-end bracing and whatnot that he'd bolted onto his setup.
Honestly kinda wishing that I'd done it that way, again, with my current notchback, since I seem to have a ton of problems with ground clearance, anyway, with the traditional Dynomax cat-back and UPR X-pipe.
