Buying a Cat C/D sports/specialist car doesn't phase me at all!! Well, that depends on damage etc!! I've seen plenty of Cat C/D's that have literally got hardly anything wrong with them!! On the other hand i've seen loads where i've looked at the pic & thought "ouch!! the driver can't look so great right now!!"
As an example i was looking to buy a Civic Type R before I bought my GTV. I looked at a few Cat C/D's!! Some of them wanted pretty much a whole new front end, both wings, lights, bumper, bonnet, slam panels, rads etc etc!! Which for me is too much, I'd only go for the lighter damaged cars. There does seem to be quite a large spectrum for damager with both Cat C & D!!