Like he said, donor cars are cheap especially if you look around. My 2000 Trans Am LS1/T56 clearly had been in a driver's side front impact but everything was repaired. I got the car for $3900 and drove it >500 miles from Reno NV to Ventura CA no problems. I asked around junk yards, ebay, and craigslist, and unless it was on craigslist w/ an automatic (which I would never do), I spent less for the whole car then I would have just for the motor/trans.
I found the donor on Craigslist, I literally searched every area listing in CA with searches from LS1, LS2, GTO, Firebird, Camarro... I had found a GTO w/ LS2/T56 for $5k but it wasn't drivable plus the guy sold it over the hour I was thinking about it. Lesson learned, good deals go fast.