Carfax will help add some clues for him. It will show him if it's been moved from another state. It will show a mileage change if the turbo dash was swapped in. It will also show if it's been totalled from an accident. All of these things are involved in figuring out whether it's a re-VINned stolen. If a car is stolen & re-VINned, most of the time, the title will be 'washed' in another state so it doesn't show as salvaged. For right now, you can look for the option code sticker, if you can find it on the trunk. You can look for the other VIN's stamped in the body.
I'm trying to think what would be the positive outcome for a person if he "publicly " finds out that the car is stolen or a car pieced together from stolen cars. I emphasize publicly here. Sure find out stuff on your own to satisfy your curiosity. I know I'm not stating here exactly what I'm trying to get at...maybe I dunno...I mean nobody wants a franken car and people want to do the right thing *if* a given person was in a certain situation. And most people will find out their car is great and what it should be,I was just ruminating with "let sleeping dogs lie".