a more exotic swap

How about an SRT-4 motor? 2.4L Turbo motor. Compact, big potential, more reliable, etc. They sound wicked as well! I would go as far as to say that the SRT-4 motor will be able to produce more power than the VR-4 motor, easily. The Nissan 300ZX TT, and the Mitsubishi 3000GT/Stealth VR-4s are notorious for being very difficult to make good power and tune. And that's in the Original cars! I could imagine that this swap into an A-Body would be a huge headache. So, I suggest looking into the SRT-4 motor.