nah twin spark does a bit for performance but not much, (higher power ignition does the job better eg. msd), the head looks like but its the 2 valves per cly that makes it shit. having said that, its been along time since I've seen that car, blue Celica with a sports seat, and i have never once seen it out on the road since it was all fixed up. can't remember if it was a 3T-GTE or 4T-GTE
they came from TA63 Celica, TA63 carina, TT142 Corona GT-T & GT-TR, 120kw 160hp @ 6000rpm, Double-row Chain, but limited sized injectors at 295cc's, turbo being a CT20 and produced between 1982-1985, there is still better engines out that are easier to find parts for and cheaper bang for buck that'll fit in a TA22 so i couldn't see any difference with a 2T like your doing
http://www.bigflea.com/corolla/index.cfm?ContentID=111
if your some what interested at all... http://users.chariot.net.au/~stmezz/3tginfo.htm