If you get all the racers Anakin will have a max speed of 735 mph.
Beat all four racers on one planet, then you can race against Sebula on any of the four courses. If you win, you get his racer. In future races, if you lose, you lose his racer.
To recharge your pod; hold the brake while racing. It my slow your pod down for a little while, but it could make the difference in the margin of victory.
Press A as the "1" during countdown fades away the screen.
In the third level of the Tatoonie races there is a shortcut about 1/3 of the way through the course. It is on the left side of a long plane. It takes off a good number of seconds off your time