1. Clean and clear title.
2. Oil leaks, radiator leaks, etc.
3. Mechanical problems
4. Electrical problems
5. Engine problems (valves tapping/etc.)
6. Transmission problems (grinds hi/low rpms)
7. Body damage
8. RUST

Just a few things to look into, but you get the point. Also it's not just for Integra's, but almost any car you would buy.