I thought I should mention this, I have had to correct a least two competitors this year so far.
If your car is equipped OEM with 4WD/AWD it is allowed in a Production Category class only, page 22, section 2.P.
If you have a car with 4WD/AWD and plan to run in Altered class for instance the 4WD/AWD system must be disabled to allow either FWD or RWD(your choice). The Altered class is a subsection of the Modified Category, not Special Construction or Production Categories.
The manner in which the 4WD/AWD is disabled must be demonstrated in the impound area. If the system is activated via software be sure to demonstate that it is disabled before running. It is better to disable the system mechanically vrs. software as questions could arise as to whether the system was off or not.
Again, 4WD/AWD cannot be carried forward to classes other than those listed in the Production Category.
DW