Long old discussion of subframe connectors:
https://firstgenfirebird.org/forums/ubbthreads.php?ubb=showflat&Number=250290&page=1

Interesting this old topic closed with a discussion with Firebob back then, about whether or not, or where/how exhaust would fit with my custom weld-in SFC setup and my integrated drop crossmember all in the way. To bring closure I will share that my favorite local muffler shop custom-bent and welded up a dual 2.5" with crossover system and it fit right into the tunnel alongside the driveshaft with no problems whatsoever, and my convertible brace still fits in the correct place with no spacers. They charged me $267.50, all parts & labor included. Nothing bumps or rubs or leaks. They did the whole thing while I watched inside of about 3 hours. It would have taken me 20 to 50 hours to do what they did. That sure cured me of ever considering doing my own exhaust work ever again. I couldn't have even purchased the parts they used for less than $300....most similar "kits" are in the $450+ range. I'm a big DIY guy normally, but some things beg to be subbed out to people with lots and LOTS of practice and experience doing their one specialty, and a tightly/complicated routing of an exhaust system is DEFINITELY one of those things. I'll never touch an exhaust pipe again, as long as this shop is still in business....

Now 2 years later. No regrets. The weld-in SFC's were one of the best handling upgrades I ever did on my convertible.