Me personally, if I was to buy a C / D cat shell, I'd keep a record of condition when it was purchased and some photos of the build up to put any potential buyer's mind at rest when, at a later date, you might be thinking of letting the car go. There are cars out there that have been heavily knocked, but damage was never recorded, there are cars that have been lightly damaged but due to complexity or value, written off and then there are serious cases (as per the Corsa posted above), where a cat C / D is appropriate. Unfortunately, most people's idea / perception of a cat record is the last example...