This Class is often used as a 'stepping stone' from Class One into the larger, more powerful classes as you can - with relative ease - convert a Class One into a Class Four.
The car used must be of a front or rear wheel drive Saloon, Hatchback or Pickup.
Modifications allowed: Unlimited tuning but the engine must be of a maximum 1130cc capacity and be one that was originally fitted to the car and must remain in its original position. .
Cars you can use: A variety of different cars are used in the modern day such as: Minis, Imps, K11 Nissan Micras and Fiats. However the Class is beginning to expand with many different models of cars.
Please check the NASA website on the link below for more details.
Rule book for class 4 On the official NASA website