(at around 32 mins) During the shoot-out between Michael et al and the bikers as the camera angle changes from front to side to back of the car the rear-view mirror appears and disappears depending on the camera angle.
When the biker is about to crash into Sam's car, the roads are dry. The moment after the crash, there are puddles on the road.
When Hunter arrives at Big Ed's house, you see an earplug in Ed's right ear (31 min). These are safety equipment for the gun fight that follows. They aren't to protect against wind noise as he wasn't riding his bike.