start with 300 frames (10 seconds) for the first cut. do the movie in 5-second cuts, then concatenate them in your movie editor. your audience only has a 5-second attention span, so you hafta keep 'em off-balance. most of the cuts will have 50-100 dead frames at the end, so you just delete the end frames. you can get into the car in 3 seconds or less, so you can allow for extra time or slo-mo with 300 frames, and still have a buffer segment at the end. you could even jack the frame count up to 999 per cut, but you'll go nuts trying to keep track of more than 300 frames in the graph editor or animation palette.