Gary,
Most cups that have been raced have seen some type crash. Everything depends on the paper trail, I.e. Owner(s) and the shop that did repairs. If you have already verified the credentials, I would buy it. Re-tubbing a car is no big deal as long they put things back to original. Porsche motorsports actually issues new VIN number when they sell a new tub. The shop has to cutout the old vin plate from the damaged tub before they sell you one.
Cup cars are very cookie-cutter like. There is maintenance routine and you follow it. Most important thing it so have a trustworthy and reliable shop yourself. Because overtime, barring wrecks, you will replace practically everything in the car except the tub itself. Even the race seats expire!. Race cars only have bare essentials and they timeout. So be prepared $wise!
Anton
