If you are playing this on hard difficulty, and are having trouble with the final car chase, my advice is to zig zag as you drive. If you drive straight you cannot speed away from them fast enough and they will literally make Swiss cheese out of you in seconds.
Zig Zag from side to side as much as you can while keeping a steady momentum going forward. This gives you a much better chance of escape and they miss more shots. Police get involved and the enemy cars usually end up crashing fairly quickly after the first couple of corners.