The 2.5" Pypes install on mine was a nightmare of a job, even for a major exhaust shop. Not sure why, but they had it for 15 days and pushed it into the corner of the workshop in the too hard basket while working on other cars instead. They had to modify or replace half of it, I could have possibly had a complete custom system for similar cost, minus the international shipping and purchase. Things were different back then.
Anyway, they reused the factory splitter location for the supplied mounts, had to cut and reinstall the hanger location on the splitter ends as they were nowhere close. I also supplied 2 new Pypes muffler mounts for use above the rear axle, that could be use for crossflow muffler systems and they didn't use those mounts at all. The only reason I can think of is that the pipe over the axle was nowhere near them, they had all sorts of trouble, cutting, removing, adding, to make it all fit. Also, if based somewhat on factory style those mounts were for crossflow, duals didn't use any further mounts except where where the tailpipes are, 2 different locations depending on splitter or straight.
Instead, fashioned a solid rod hanger off side behind the mufflers and before the bend, and attached to new D-mounts bolted to where my existing subframe connectors installed. It was neat, but not really what I wanted. But after getting screwed around with engine shop, paint shop and exhaust, I just wanted to get it home. It had been away for 2.5 years for a few months work.
There's new reproduction mounts out there now, closer to stock style. I had new splitter hangers that were better than my originals but not very original looking, nor did I care too much at the time. And I still have the photos of the Pypes muffler mounts that went unused and later sold locally for giveaway prices.
I'm not sure if this was where the issue started or not, but i wanted the splitters to mount at the exact location as stock did. There were small round dents on the underside lip of the rear guard where the originals had hit at some point, so handy to line-up. That meant moving the hanger strap along and possibly upset all the over the axle area prior. Have noticed other systems exist differently to mine, I had them splayed out as much as could be for the larger size and clearance. Even with lower suspension, and 285 rear tyres, there's good clearance, even around the fuel tank rear corners.
Be aware of the rear brake hose clearance too. On factory models with dual muffler they used the small bracket to offset the brake hose mount on the axle for extra clearance. You may or may not find that on an aftermarket system. Mine has it, I can't recall if it actually needed it, but it's further away than it would have been so a bonus.
After all that rambling, no there's no mounting points other than the tailpipe/splitters for dual muffler cars and above the rear axle for crossflow muffler cars that didn't normally use one for tailpipe. I supplied them anyway just in case, and since without the cat and brackets off the trans mount, there's no factory mounts between engine and crossflow mounts, for a custom system. I also supplied 2 sets of the cat brackets, in case they could adapt something either side, or for ideas, luckily didn't.