When the gun thug is in the car next to Jim and Stacy, his passenger window is down. After the camera angle changes as the car moves forward, the window is up.
The shooter used a silencer on a revolver. You can't silence a revolver because there is an opening after the chamber for all the noise to escape. Even if he used a semi automatic with a silencer, people in the store would have heard it. It is still quite loud.
In addition to the error involving the use of a silencer on a revolver, the silencer shown was far too small to be effective on a 357 magnum, which was the caliber stated for the gun.
A felon with 29 priors convicted for murder during a robbery would not be paroled after only 5 years.
Both of the Mazda RX-7s driven by Hooker and Dunston were the same car. Neither had any license plates, and both had a white sticker in the same place on the windshield. When Dunston pulls up to his apartment later, only the rear corner of Hooker's RX-7 is shown, revealing a similar model was used for that scene only.
Hooker asks for an exact duplicate of Dunston's car and tells Corrigan to check the rental agencies. Dunston's car was a 1982-85 Mazda RX-7 GSL, a sports car not available for rental.