1987 Audi Quatro

Im looking at a 1987 Audi Quatro turbo, i think its called a sc500 or something like that (not sure) and i was wondering how reliable it would be if the owner kept it in good shape. Ive also heard that replacement parts are kinda expensive and hard to find compaired to japanese & american cars and i was wondering how much more expensive they are in general.

Thanks.

I just thaught of a few more questions, I was reading something and it said that some of the Group B Audies had 450-600+hp (one with 1000hp!) and i was wondering what this car can handle on stock internals. also how is the aftermarket with these cars? I cant seem to find any good websites yet. Oh and I also wanted to ask your opinions on what Audi would be the best to learn to race in is.

Oh and sorry this is a question not involving the 94-01 A4/S4/RS4 but the other Audi forums didnt look very active.
Thanks again

reliable...parts are a lot more expensive and harder to find though