Also known as minimap. It's purpose is to show a bigger part of the level so the you can drive faster in unfamiliar levs. Big minimap is useful in battles. Since elma 1.2 it's size have been adjustable.
Nitro patch is an unofficial patch which works only with elma 1.0. It is illegal to use in any cups and it adds 10 minutes to your time. With the patch you can adjust for example gravity, acceleration, time and elasticity and you can be invulnerable. It's certainly worth to try, but it's not meant for regular playing. Get it from zworqy's site.