I'm thinking it is simply the lack of spare parts.
These guys are known for carrying a Ton of spares for their race cars.
I'm not even sure you can order up half the stuff they will want to carry yet.
I'm only racing a 4 hour race this coming weekend and for the Rzr, I will have :
(2) spare wheels
(2) lower A-arms
(2) uppee A arms
(2) lower radius rods
(2) upper radius rods
(2) ball joints
(2) heim joints
Left tie rod
Right tie rod
Spare belt
Spare belt cover
Spare hub
Spare rotar
(4) spare lug nuts
(4) spare wheel studs
Dozens of bolts to fit everything imaginable
For the YXZ I will have :
Nothing.