Nitrous in Crashday comes pre-installed and the power output is the same for every car. It's also possible to disable nitrous in singleplayer or multiplayer. Disabling or enabling nitrous won't affect a vehicle's top speed or handling.
Redline Edition allows players to change the nitrous colour from 12 various colours.
Pre-release garage screenshots depict a cut feature, upgradable nitrous. Icons and strings can be found in original game files.