couple questions.
 

im going to be buying an 84 mkII. on the back it says CELICA GT but on the front badge it says celica supra. which is it?

it needs an ECM and i'm looking on ebay and it says for 2.3L 2.4L's but every where i look it says the 5mge is a 2.8L and napa wants 455 bucks for one. i'm getting the car for 200 bucks because i know the guy pretty well.

and what is the "performance " package? because there are 2 ECM's at napa, their the same price but one is "performance" package.

Celica GT and Celica Supra are two different cars. I believe the Celica GT has a 22RE (22REC if it has CA emissions) engine in it, whereas the Supra has a 5MGE. I believe what napa is referring to is whether the Supra (if it is in fact a Supra) is a "P" Type or an "L" Type, meaning performance or luxury. I'd get on wikipedia to find out how to tell what yours is, as I am not a MKII guy (just haven't owned one yet)

EDIT: Forgot to say, 5MGE is 2.8L, 22R is 2.4L