Here's some random tips.

- Feel panel edges. If there is a ridge or a line along an edge, that area has been resprayed. Factory paint is smooth all around.

- check the sparkplugs if possible. Oil on a sparkplug is not good.

- Hit every switch in sight. (heat, ac, lights, wipers, ...)

- Take a look under the hood, make sure the battery is fresh. These cars sit on deal lots for an extended amount of time. Batteries die over time.

- When you start the car, keep your ear open for anything. Walk outside of the car and follow the exhaust sound from engine to trunk. If you hear any spuddering, you got an exhaust leak.

- On the test drive, accelerate and brake hard to expose any other issues. (metallic rattles, shakey stops, metallic clicking from the wheels)