Can't be bothered to mess about with all that tedious precision destruction? This cheat will help you out no end. Just drive your vehicle right alongside a building and use Z button. Normally this would make your driver get out but if the door is blocked he'll just shout at you. Keep holding the Z button, and a few moments later the obstruction will magically explode.
On timed events, you can obtain a Turbo Star by accelerating right after the last beep, when the light turns green. If timed correctly, you will get a turbo start.