ok, i've been off forum for a few months, but i'll chime in
mr2: i'm guessing you're looking at a later body style which i haven't heard good things about them
300zx: good luck finding one, when i was in the market for a sports car, they either had way too many miles and were in my price range, or they were garaged with very few miles and way out of my price range. i never even test drove one because those two factors lost my interest quickly
3000gt: good luck finding one of those too. ^same reason sweet car though
i bought a 94 z28: good miles on the clock, almost new condition, enough power to do stupid stuff in, pretty nimble(although could use stiffer springs, i'm gonna get coilovers). the brakes do stop well, but could use bigger disc, i've over heated them quite a few times. and milage: driving like an idiot in stop and go traffic i would get 17mpg's. and driving 90+ on the highway i got almost 30mpg's. (although any 6 spd should do the same)
not trying to sway you one way or another, just wanted to chime in. i'm currently going through an older european car stage, the only problem with factory turbo's is a weak drivetrain :-P . oh yeah, i hate dsm's
oh yeah, miata's are monstors, i used to think they were girlie cars, but go to an autoX, my jaw dropped