When Toothpick and his gang are leaving the confrontation with Loc Dog and Ashtray at the "40's & 9's" store, they drive in reverse in a Pontiac GTO. However, you hear a gear change - Pontiac GTO's didn't come with two or more reverse speeds.
In the scene where four guys pull up in a BMW pointing guns at Ashtray and Loc dog while they were standing behind the mail truck, Loc dog points his gun at them. The guys in the BMW take off in reverse. You can hear the car changing gears. No car changes gears in reverse.
When Ash tray 1st arrives at his father's, he States that his father is just a few years older than he is. When his father ask him why he wasn't invited to the party Ash tray told him he had to be over 18 to attend. If that's the case Ash tray wouldn't be able to attend the party.
During the final drive-by scene Doo Rag is seen on the lawn before toothpick and his gang starts shooting but when Ashtray runs away from the house during the shootout, in another shot we see Doo Rag just arriving.