It looks a bit rough, but for that price who cares!
and its nothing a dremal tool or some work with a file can't fix.
About the 4agze, yeah should be an easy almost bolt into the AE82.
Just remember you need to convert the whole car to fuel injection as well. and swap in enoug of the loom to run the car.
Any reason why the stock ECU won't work? It should, even with the cams and boost pully.
Running an aftermarket one sounds like more trouble than its worth.
check out
www.twincharger.com for good info on swaping.
as well as
www.mr2.org for heaps of 4a stuff.
and theres some threads in the Corrola forum as well.