The 3.8 used an Eaton M90 charger. 90 cubic inches of displacement per revolution. It is small...probably a little too small for a small V8 as you would have to turn the darn thing so fast to make an appreciable amount of boost that it would make more heat than pressure (which is why we refer to the supercharger as a Heaton). You'd probably be better off finding a M110 from a Cobra or a Lightning. They're still quite small but they will probably do a little better as far as the heat situation. I believe they have produced an even larger supercharger as well now...but can't remember what they were put on.
Lightning/Cobra eatons are fairly common on Ebay. Also check some Lightning websites as they are commonly upgraded to a kenne bell or whipple (or changed over to a turbocharged engine).
It shouldn't be that hard. Swap everything over and get the pcm, wiring, etc. I wouldn't suggest putting more boost than factory, your bottom end may not be able handle it. Unless you swap the whole motor.
Lots of custom fabing to mount the intercooler. Maybe swap the heads, do a little custom exhaust, and whatnot.
3.8 to 3.8, should be pretty much straight forward.