Some cutdowns have been used for drag racing. At scooter races, cutdowns often race in a separate category called the "specials", which is for cutdown and heavily modified racing scooters. The other scooter race categories include stock races with relatively unmodified larger scooters (152 to 250 cc) and "small frame" races for scooters with 136 cc or smaller engines. For races, scooters usually have to have accessories removed, such as center and side stands, mirrors, turn signals that stick out, and luggage racks. Scooter races often disallow performance-enhancing fuel additives such as octane booster.