I purchased my car as "ready to drive" and paid a pretty penny for it too.
Shortly after purchasing it I decided I wanted to upgrade the brakes to and wheels........ 2 years and $70K later my car still isn't finished.
I decided to go with a newer corvette motor, suspension and all the goodies that make a good track/street driver.
If I had it to do all over again, I would either purchase a car already done or I would have bought a completed shell from someone like Mikes Custom cars
http://www.mikescustomcars.com/
Yes, shelling out $20k for a complete frame and body seems like a lot of cash however, the fact the car is ready for finish paint when it arrives at your door is a major relief.
I have another year and $20K (including paint) before my project is completed. My point is, if your looking to build a pro-touring car, buying a ready for the road car is more expensive than buying a good shell.
Good luck,
rich