It also depends on what you want from the car when you're finished. I have a friend in Florida that got sick of rebuilding his RX-7's engine. So he yanked almost the whole drive train and threw it away. He dropped in a crated LS1 motor, mated it up with the transmission from one of the Corvettes that had the LS1 (I can't remember which) and used the wiring harness from a Cadillac that had the LS1. He used a pre-built racing ECU that was made for the LS1 and dropped in a custom built drive shaft (surprisingly they aren't that expensive ~$1200) and fabbed up his own custom exhaust headers (no cats, no muffler). The car is a hard charging screamer now. But he worked really hard on it, and spent a good deal of money doing it, and he did almost all of the work himself.