Like most classics the only ones likely to go up in value are mint, low miles un-modified, FSH, low owners vehicles. There were a couple that fitted that description advertised recently at about £8000 Iirc (I think both sold quickly). The only problem with buying one of those cars is you use it and it will depreciate to the value of the rest of the cars that have had a more normal history. I dont think the "average" Corrados are going up in value despite what most owners would hope. Just buy a well looked after one, drive it and enjoy it, if you're looking for an investment then I think you'll