This can be a tactically useful addition to your car and is not considered a weapon for the purposes of Races. It takes space like a weapon though.
When used, the Nitrous Booster will increase your speed by up to 15mph per turn for approximately 3 turns. Be VERY careful when and where you use this booster. You can EASILY lose control of your car if you are in a turn or you have the wheel turned even slightly.
Unlike other weapons, it doesn't matter where you mount a Nitrous Booster.
Using the booster will dirty your engine lowering the effective horsepower and speed/acceleration. This means that you will see your engine take temporary damage from use. This damage is removed after the event.