[Formulajones]

That will be a tough go Will.

I've bought just head pipes separate, and just tail pipes separate, but as far as I know I've never seen the over axle pipes separate for a transverse setup. I don't think that is offered anywhere but if you give Pypes a call, they might be interested in selling the over axles pieces, along with their transverse and the tailpipes needed to go with it.
If you go with the Pypes transverse muffler, you definitely need "their" over axle pipes and tail pipes because they construct their muffler differently with the inlet and outlet opposite from side to side, so standard style transverse over axle pipes and tail pipes will not fit their muffler.

As far as F-bodies go I prefer transverse systems. There are 2 systems I like to use, and have used several of both of them.

The SG70 transverse setup from Pypes, and the Dynomax 89021 transverse system.

For the record, the Dynomax muffler has the standard inlet and outlet configuration just as GM did it.

Just an FYI Will, as long as you're not hooked on keeping the "X" in the system, I'm betting you can replace the whole setup with the Dynomax 89021 "H" kit cheaper than trying to piece the back half together. Those Dynomax systems are still priced under $300 for the entire kit.