When Steve is working out in the boxing ring, the back of the gray shirt worn by his sparring partner alternates between sweaty and dry.
The HPD and POLICE lettering on the helicopter are just pasted on banners which are easily noticeable. The Hughes 369 (N9014F) plays many other roles.
The chase between the police motorcycle and car was sped up using the frame rate to the point where the motion has an unnatural almost slapstick comedy effect.