Read this.
It's for the '70-'77 Celica but the motor swaps are pretty much the same.
http://members.iinet.net.au/~stepho/celfaq.txt
http://members.iinet.net.au/~stepho/celprod.htm
If you want straight forward then go for another 22R-E.
They are good strong engines and a new cam and aftermarket exhaust can do wonders.
The turbo 22R-TE isn't very powerful in stock form but the internals are stronger than the normal 22R-E.
I've been told that they can be made to perform well when the turbo and cam are replaced.
The engine bay is pretty wide but not very long, so 6 cylinder engines aren't easy.
If you don't mind a more involved transplant then try the Lexus 1UZ.
http://members.iinet.net.au/~stepho/mods.htm#CarinaV8
The 1UZ weighs only a tiny bit more than the 22R-E.
Down side is that Toyota only made them as auto.
Dellow in Australia make manual bellhousings for them but it gets expensive when you include a good clutch, a Supra gearbox, etc.
Also, some people have put in Chrysler 318 V8's and Ford 302 V8's into the RA65 with good success but I've always had question marks about how the weight balance affects the handling.
- Stepho