You'll need the engine, a S-series or E-series FWD tranny(E-153 from an MR2 would be a good choice), ECU, shift linkage cables from a GT, igniter, and lots of other stuff.
It'd be smart to get a clip. Do you know what generation 3S-GTE you want to swap into the car? Are you going to do the work yourself?
Also, this topic has been discussed many times...if you do a search, you can find all kinds of information on it. >

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