I'd think 2.5 has it right. If the car overheated or starved for oil and was driven, that's where you'll end up with internal "hidden" problems. Have a look at the underside of the engine /trans for leaks, also look for antifreeze leaks or green stains anywhere low down on the car. Also if the impact was enough to damage the front end, you may have some trans damage. Try to drive it in all gears, or negotiate the price down. Have a look under the car at the trans mounts. see if they look pushed back or out of whack. A look at a similar model just before looking at the purchase car would be of great help.