Come out to a porsche club autocross this spring and ask to ride along. They are a blast! They are also way overpriced in my opinion even in poor condition. We had one at the shop (same as Megaman above) needed full brake job, fuel line work, and suspension work. She wouldn't take 2K for the car even though it needed like $1200 in parts. And as far as a 914-6 goes, if you are doing a swap, then for the love of God do not buy a 914-6, those cars are too rare to tear apart and put an American motor in.
For those that don't know the 914-6 has the flat six out of a 911 in it.