If you keep the UTV mostly stock, you're fine. No need for bulkheads, firewalls, external cutoff switches, fuel cell, etc.
If you modify the floor or rear bulkhead plastics? You have to then meet the U4 general rules for those things. Same if you go with a fuel cell. If you get rid of the factory ignition switch, you need to install a cut off switch. Stock stuff passes for UTV's.
This year's tech was a breeze. The checklist was easy:
Powersports based drivetrain under 1000 cc?
Front and rear bumpers?
6 point cage for pro, or modified 4 point cage or better for sportsman?
roof?
doors?
seats with harness slots?
date coded harnesses mounted correctly and at the correct angles?
arm restraints or window nets?
two fire extinguishers, one inside, one outside?
rear amber light?
safety triangles?
horn or siren?
first aid kit?
mirror(s)?(though I don't believe it was on the actual checklist)
Then they checked vehicle numbers, helmets and firesuits. I waited in the tech line a long time, but once up front, it took me maybe 3 minutes to pass. And once you pass you get a metal tag, so you can breeze through the express lane at future races.
Engine wise, you must start with a powersports based drivetrain that came from the factory under 1000cc. After that you can do whatever you want. Nitrous, turbo, boring it out, etc. I will point out that almost every car out there had a stock engine.
