There was a time when Driver was one of the very best franchises available. If you love the idea of driving mixed with action and you've got a PSP, you should pay attention to Driver '76. It's worthwhile.
Unlock Sumo Racer
If you want the sumo racer, there are two ways to go about it: You can either complete all the missions in the Story Mode as well as all the side missions with the best time, OR you can opt to just destroy all the cars in the destruction derby before time runs out. Good luck!