The plate on the Mustang is clearly a prop, as the letters and numbers are uneven- the PS96 is lower than the 14E. On Illinois plates, the letters and numbers are all at the same level.
Officer Burgess practices bad tactics when she encounters the gun thug in the alley. Since he had already pulled and fired, there was no need for her to give any warning before returning fire, yet she did so and lost the best opportunity at stopping the gun thug. Later at the suspect's home, she holds her gun sideways, which is known as gangster style. That is not how police officers are trained to hold their guns as it is an inaccurate way to shoot.