Ok here is the deal, and the real deal. I have worked for the largest dismantaling company in CA for German, Italian, and British.
First off most people that have bought a expensive car and have a high amount of bank roll dont care about insurance. They just buy the car out right and say if something happens they will just buy a new car. They get the cheapest insurance just so they would be legal to drive. Then if something happens they call a local dismantler that buys cars like they have and say " hey i have a clean title whatever make and model that has damange and im trying to get rid of it" so me being the person thats trying to make money on that id say "a 2005 bmw 525i with front end damange, ill give u 15grand for it". I know that the car needs work, but I can get a bumper from the back of the yard, send it to my paint guy, have him fix it for nothing, and have all of the other parts bought non oem for nothing. Have one of my part pullers install all of it for free and only be in the car for like 17,000. Then have some used car dealer come buy it from me the next day for like 20,000. Then I make 3grand in a week after all costs.
For example I got a ferrari 360 from a guy in portland for 45 grand. It needed a new hood, new front bumper, new side skirts, new wheels, and all front hardware like oilcoolers, ect. I already have all those parts in my yard so i just send them to get fixed, (fiberglass is cake to fix), get a cheap paint job from my guys, get new airbags (the most expensive parts) and get a guy to clear the computer so no lights come up on the dash and I make 35-50grand. Because they guy never clamed it, its not on carfax, its clean title, you can as 30-40grand less than other 360s out there, people hop on it like a hot blond just asking to get some.
The moral of this story is dont buy used cars from used car dealerships. But only cars from dealerships that sell new cars.
But lets just say you bought this car that the guy posted about from a BMW dealership, buy it, if its been in a wreck, and you can prove it, and they dont know or didnt tell u, you could sue the fuck out of them. Walk away with a new M5, 760li, and a 335 just for shits and giggles.