Yep, been there, done that. I've built 200+hp 20/22r engines for my Celicas. Been through several sets of carbs and done just about everything you can think of to do to these heads. I've had 8000rpm Rs. I can tell you it's possible to get 160hp with a weber 40DFEV, single downdraft synchro 40mm 2bbl. The EFI, I'm sure, is not that hard to get that level power from with the proper tuning, probably have to ditch the AFM and go MAP, or use a Supra AFM. A stand alone is definitely a good direction to go, but I'm still trying to verify whether a piggyback will work with the 22RE ECU.
I think it will, but does anybody know if the Greddy e-manage will work with the 22RE ECU? I'll be using the '89 to'95 electronics.