Engine Swap

Ok so i have a '92 Legacy Sedan with the 2.2L in it and i was looking to get a faster engine in it. I would like to keep subaru parts so i can keep my AWD. The two options i am looking at are the 2.0 Twin Turbo and the 2.5 w/ or w/o turbo. First off i need to know if the 2.5 will even fit in my car. Second off which would be the fastest possible engine i could put in there? Thanks.