When Cory tips Marv off about the Porsche, a blonde woman in a black bikini walks by in the surf. This same woman can be seen by the tower when Cory returns to it.
When Marv shoots the police car, he makes several bullet holes in the windshield. When the police car catches up with him, the windshield is intact.
During the wide shots of the dory race, the men in the boat are obviously not David Hasselhoff or Parker Stevenson.