Increased Survival in Last Man Standing:
To increase chances of survival chances in a last man standing contest, simply circle the outside of the arena. Doing this will not allow you to get any damage points, so do some damage beforehand.

Rival Car in a Last Man Standing Contest:
There is one car in a last man standing contest that will follow you until it is destroyed. It is an all black car with a red, white, and blue hand shaped emblem on its roof. This car has more armor than anyone else on the track. If there are two cars remaining, including yourself, it will usually be the rival car. It likes to hit you from behind, as well as sideswipe. The best way to survive against it is to stay away.

Unlock everything
To unlock all the cars, tracks, and game modes enter: X, X, Square, Square, Triangle, Triangle, O, O at the main menu. You will hear an engine rev if you did it right. NOTE: when you are entering the code you will go to different menus, don't worry about it, that's normal.