Sully's Auto Mart, is a car shop in Grand Theft Auto IV. A commercial can be seen sponsoring it on television. The shop is not actually shown in the current version of the game but the area in a TV commercial was filmed at Willis Wash and Lube in Willis, Dukes, in a early version of GTA IV. The shop sold cars in very bad condition, some with bulletholes other have broken lamps. Its possible that they are stolen since one car has blood on the broken windshield.
It could be a possible reference to Sully from The Warriors, another Rockstar game. Sully in the game is the leader of the Orphans gang. He drives a car identical to the last car shown in the ad.