By starting a New Game at a certain point in the intro sequence, you will get a faster RTA load of the Garage than normal. The timesave you get depends on how slow your Xbox is at loading.
The timing isn't as precise as it looks - if you time your A press to when the beat drops (assuming there's no lag on your system), you'll usually get it.
It's unknown why this works. This does not affect IGT, so the timesave you get is restricted to RTA only. (I believe it's due to the zoom cancelling the fade effect).