I have a retired 04 cruizer (crown victoria p71)with very high miles and i bought it that way. It now has 296,xxx on it roughly and runs great oil is clean even when a change is due, tranny is clean, doesn't smoke. It still has butt loads of power and doesn't knock. It was a transport car. Been a good car except for all the paint flaking off. I wonder if they replaced the motor or are they this good? Every thing works too, and it is in very good shape.
When I purchased the car from the local Ford dealer, I got a large stack of service tickets and work orders from the police department that originally owned the car. You could probably find out from the original owners if there were any major components replaced or rebuilt.
The car came from the auction and i think maybe a car-fax would find anything? I do not think the police dept. wants me calling on one of their old cars, lol.