Well, my grandpas 87 Regal came from the factory with the 307, 3 speed trans and 2.14 open rear. (Yes, my grandpa really did buy it new back then)
That wasn't exactly fast enough for me, so I fixed that.
Dropped in a whole 87 GN drivetrain a few years back.
My buddy and I almost put one in an older nissan Z that he had at the time. Found an 86 GN setup, but then he wrecked the Z. It was a good idea though.
My swap was fairly easy, considering it was going into another Regal anyway. It was all the minor stuff that was needed to complete it that was the real pain. Wiring, computer, exhaust, gas tank, fuel lines, electric fan, pump wiring, etc. At least I dont have to worry about the crappy powermaster brakes though!