There are 3 variant of wheels.
1) Alu
2) Baroka
3) Stock

If you want to change wheels on the car, it is simply. You must open folder (Alu,Baroka,Stock)and copy Left.dof and Right.dof and paste to the main folder of car
(mercedes_w126_us-special)and replace all. If you dont like this wheels, copy wheels from folder (Stock) and paste to main folder of car.