The family own a Mercedes-Benz W126 S-Class, and is normally referred to as George Bluth's car.
George was quite particular about keeping the car clean, not allowing Michael Bluth to eat ice cream inside (though he relented, resulting in ice-cream stuck to the roof).
Many years later, while George was in prison, his children treated it terribly: G.O.B. scorched part of the car while attempting to perform an illusion, Lindsay Bluth Fünke spilled nail polish all over, and Buster Bluth had various items left inside from his archaeological dig (including a skull). ("Charity Drive")