If you take care of the car, it will take care of you.......My Gs-R had 143,000 when I bought it runs like it has about 50,000. Thats because the owner took care of the thing like it was his girl or something.

A few words of advice:

1. Try to buy a used car from older people, so the chances are greater that the car wasn't pushed too hard.

2. Buy the car from someone who is well off, so you know they didnt slack off on maintenance because of financial issues.

3. As a rule of thumb, try to stay away from cars that were already modded.