i'm considering buying a silver, 2000 audi s4 from a guy who lives a couple of miles away from me. the car has 140,000 miles on it and it's $4000 and it's in really (or appears to be) good condition. should i be wary buying a car NOT from a dealership?? it's my first car, so i can't afford to constantly take it to the shop and i know audi's aren't cheap to fix!