youll probably get alot of people telling you to do a search, but ill try to post the little bits i understand about the car(i have a 89 N/A)
the S/C models i believe were all the same car, maybe some small variations, like the LED taillight, but nothing to big to worrie about, a good and bad thing(at the same time) about the car is that it had a suspension that was more prown to understeer, which made sence overall, but the problem is and was that the mki(and maybe mkii) mr2s are known for having a bit of flex in the suspention(Macpherson strut) causing the wheels to toe in/out(mainly a problem when the rear wheels do this) this can be minimalized by either upgrading suspention components(spherical bearings) or by making the suspention sway less(stiffening rear suspension), but instead toyota had it setup so that the rear still swayed just as much as the N/A, but with (i believe but not sure) stiffer compression in the front shocks, anyways this led to the car having predictable understeer near the limit and then at and over the limit the car would change toe in the rear tires and the car could spin very quickly, so its not the easiest car to drive at the simit with stock suspention components, but i also havnt heard any horror stories, so dont dwell on it, just know its possible
if your planning on modifing the car this isnt really a issue
Other things:I have T-Tops(all S/Cs did) and id recommend them if you like that sort of thing, dont worrie about rigidity too much, the cars not bad to begin with, and theres tons of ways to stiffen it if you really want to
The 4agze(supercharged mr2 engine) is probably the best bang for the buck power wise, a pulley alone can get you up to 160 something whp, only downside is the sc12 supercharger does start running out of steam at higher power ratings, but the 4agze block is a good place to start a Turbo fabrication(again best for the money for doing a turbo)
Really sweet engine noise coupled with a supercharger=sounds like a jet!
really reliable up to 200k, after that it usually depends on owner
hope if you do get a s/c you enjoy it