Engine Change in a 92 Celica ST

Hi, just kinda starting in upgrading my celica. Currently i have a Stock 1.6L in my 92 ST. I've been really wanting to do some work and get this thing beefed up. I've been hesitant because its a high mileage engine (120k) and im starting to get a knock (or a rattle) inside the engine. My friend seems to think its a busted piston, which would make sense since i seem to be losing power. But anyway, I was thinking of replacing my engine with a MR2 3S-GTE. I found a pretty good deal with the engine, tranny, and fuel pump for $2.5k. I just wanted to know if it would fit, would the tranny even work in this car (since the mr2 is a rear engine, rear wheel drive), and what else i would need to replace. I know that I would need to replace the computers and such, but anything else? Any Ideas and I would be greatful.

Jim