Three month bump because I'm back on my bull**** again.
Turns out the clutch was slipping - to anyone else planning a t5 swap, ensure your trans is fully flush with the adapter plate on the bellhousing. I put the bellhousing+plate in the car first and then attached the trans because it made it easier to lift without a trans jack, and mine was off enough to cause uneven engagement of the pressure plate. Fixed and the car is now slipless.
We're back to bucking hard if you floor it again. The girlfriend followed me on a test pull and said that when the bucking occurred I shot flames out the tailpipe. While very cool, I'd prefer speed instead. Since my last post, I've switched to NGK bpr8es plugs gapped to 0.025". bougicord plug wires, inspected and cleaned the distributor, running a reman'd 012 maf, new redblockpowered chips (thanks cam, my afr's are finally healthy). IAC and ignition amp have been replaced, tried advancing and retarding the cam gear, tried bpr6es plugs instead, all with no change. I'll try to grab a video of the bucking if I get the chance, but anything else I should check?