The GT Challenge in the Ultimate Cup Series has several sub-categories: UGT3, UGTX and UGTC.
UGT3: These are GT3 cars with the possible inclusion of the Renault RS01 ( in GT specification) and the Solution F FOENIX (also in GT specification).
UGTX: This class is designated for GT cars admitted by the promoter. The performance capabilities of the UGTX cars will be inferior to that of UGT3 cars.
UGTC: This class is for GT cars that raced in one make series or in Challenges within their respective regulations. The technical regulations for these two categories are as used in their respective series, in the applicable period to the car entered.