Well, I would think that there would be two schools of thought here:

1) Really hard / Impossible:
Check out all the problems others have had swapping motors in these cars. See HDDP's SRT-6 conversion woes. Then there was someone putting in a V-8, I can't remember who. Anyway, the short answer is that you'll need lots of time and LOTS of money, and even given that, it is fraught with problems.

2) Not too bad if you're willing to give up a lot:
If you're willing to junk the drivetrain from the differential forward, and junk the ECU and anything attached to it, pretty much junk the electrical system (especially the ignition system), and junk the exhaust system, then it probably wouldn't be too bad - assuming that there is space in there for a small block Chevy motor. Of course, you'd have to buy custom everything, and even fab up engine mounts. But if you're into that, go for it. But it sounds like you want to pay someone to do it. Good luck with that. I hope you have deep pockets.