i am not exactly sure about the instalation of the engine but i do kno a few things...
you should expect to pay $1,500 to $3,500 depending on what ear it is and what the condition is...
another thing is that the T in 3s-gte stands for turbo the N/A engine is just a 3s-ge, and i believe all the turbo mr2s come with an intercooler...
to answer another one of your questions is that yes there is a big difference between years depending on where it is from also...
usa: 90 + turbo 200bhp
usa: 94 + some minor upgrades but no hp increase
jdm: 90 - 93 225bhp
jdm: 94 - 98 245bhp (ct20b turbo)
(usa 90 + & jdm 90 - 93 = ct26 turbo)
also the newer the engine the better because every year they made changes to the engine to improve certain things...
also if you see that N/A mr2s have 2.2L opposed to 2.0L turbo, its done for a reason, go for the 2.0L
i hope that helped a little