Heather's rape scene was heavily cut for R rating. Originally the scene was lot longer and more brutal with all gang members taking turns on raping her, and she was originally hit three times by Jake instead of just one like in final version.
The BBFC (British Board of Film Classification) demanded a total of 24 minutes worth of cuts to the film before its release in the UK. At the time, the BBFC had a virtually zero tolerance to sexual violence, and the use of a crossbow.
When Jake follows Vince to the alley in his car to run him over, the person that Jake is aiming for and ultimately hits is obviously a stuntman. We do see Vince once he's bleeding on the pavement.
Brenda: [has the upper hand on Jake]
See? I told you to stay where you were. Now look what you got yourself into. You know what you look like? You look like a pig in a slaughterhouse, ready to butcher.
Principal Underwood: [Brenda is standing in Underwood's office after the fight with Cindy]
Now I'm sorry about your sister, Brenda. The police are doing everything they can. But she shouldn't have been there in the first place.