Unlimited AWD was only the format used in the Super Lap Battle. Below is a description on how they format different classes. CT230R was in unlimited AWD because it was limited by tire used and also by it's drive train.
Unlimited AWD don't form a Class/Type/Genre/ whatever term you might like to call it like a GT500 car, rally car, DTM, or F1 cars.
Class/Type/Genre/ or whatever term, Tuner gave it its identity. Racer doesn't.
http://superlapbattle.com/blog/wp-content/uploads/2010/06/SSTP-2010_Rulebook.pdf
A) STREET CLASS
1. Full interior must be retained with the exception of the items below:
a) OEM seats can be changed out for approved racing seats.
b) Factory panels may be cut to allow for safety items (roll bar, harnesses etc…

.
c) Rear seats may be removed.
d) Exceptions may be allowed but must be signed off from a NASA tech inspector
and Super Lap Battle event official.
e) All cars must retain the heater core but AC may be removed. .
2. Tires must have a minimum UTQG rating of 180.
3. NASA is managing vehicle inspection, timing, and scoring. Your vehicle(s) must
meet the basic requirements for street vehicles (HPDE) as stated in Section 11 of
the NASA CCR, found at:
http://www.nasaproracing.com/rules/ccr.pdf. Ensure
your vehicle will pass inspection. Contact us if you have any questions. If you arrive
and your vehicle is deemed unsafe, it won’t run.
B) LIMITED CLASS
1. Limited Class vehicles must have legal registration in their country of origin.
2. Windows must retain the factory glass.
3. Tires must have a minimum UTQG rating of 80.
4. NASA is managing vehicle inspection, timing, and scoring. Your vehicle(s) must
meet the basic requirements for street vehicles (HPDE) as stated in Section 11 of
the NASA CCR, found at:
http://www.nasaproracing.com/rules/ccr.pdf. Ensure
your vehicle will pass inspection. Contact us if you have any questions. If you arrive
and your vehicle is deemed unsafe, it won’t run.
C) UNLIMITED CLASS
Unlimited vehicles are bound to the following rules:
1. Tires must meet standards per section III however, no minimum
UTQG rating required