Stock suspension (shocks and springs reworked), motor and cage.
From UTV Underground:
Starting dead last, racing veteran Ray Bulloch would pilot his Textron Wildcat XX through the field and put at times up to 30 minutes on the next fastest N/A class racer. While Corry Weller in her Weller Racing Yamaha YXZ 1000R and Seth Quintero in his Polaris RZR XP1000 worked feverishly to chase down the checked out Bulloch, it wouldn’t be enough by the time they reached the finish in Beatty, NV. Bulloch would finish over 17 minutes ahead of the next fastest N/A and give Textron their first ever Pro UTV desert racing win. Making it more impressive was that Bulloch claimed at the finish that the machine competed with a stock suspension, motor and cage. Minus the required safety upgrades to make it legal to compete, this machine completed the 530 mile course in spectacular fashion and made a statement about the durability and performance quality of this new platform.