Not as "exotic" as an LS swap, but a 302 and T5 can be had for around $1500 with the right parts to make around 300hp/300tq at the wheels.
Figure that a T56 for an LS swap usually hovers around that range, and the motor is about twice as much, and you see where I'm going. LSX subframe is $1000+, headers are either $$$$ or time....and a 1k car rapidly becomes a 10K money pit from which there is little hope of return.
Since I can't seem to find a reasonably priced m50 or 52 swap, I'm seriously looking at doing something like this...
www.e36v8.com has some pretty good pics and a cheap install DVD/manual along with bolt-in mounts.
IF I could find a decent m50/52 conversion for the right price, I'd probably go that route and then turbo it when I was done....less work/bolt in.