Never heard one complaint from the anyone riding in the back of my max. As a mater of fact, it is almost impossible for me not to have a full car. Now, I will agree that it is more fun in the front than in the back, but as for the ride being horrible, I'm not so sure of any difference. Dealer will tell you anything for a sell.Yes 500 miles is nothing if it wasn't ran hard, jumped or dropped off the side of cliff or something. Should of had it's first oil change done.
Funny cause you will find more X3 MAX up for sale around 500 miles due to the fact they have the same drivetrain as the 2 seat which has much more maneuverability and lighter weight, the back seat in the MAX rides horrible for passengers if you are aggressive at all.
One reason I know is a family member just traded their MAX in for a 2 seater and the dealer as well said it was fairly common on the buyers remorse choosing the 4 seater over the 2 seater however if you have to haul more than one body then the MAX it is.