I skimmed this thread and can answer many of the questions here.
First of all I will say top, top end UTV's are <$100,000 including labor to have built by the top shops. I had multiple quotes in this range. In parts you can do it for $50,000 - $60,000 and that includes a great deal on a basic RR with no options.
Secondly I will say I ordered the twin CT RaceWorx chassis to match the winning chassis. I asked for Cheney's 2020 replica months ago after speaking with Kyle and CT, after multiple communication issues and delays with CT I backed out of the order and decided to build my own... meh.. no comment. Cheney does not get turn keys, CT makes him 1-3 chassis a year and he finishes them. I use a ton of CT parts, they are awesome, but was not going to go in $$$ with the responsiveness I was getting. CT makes bad assed, really nice stuff.
They are all surprisingly stock. Mine will not be too far off any of those cars. Besides they are my shitty welds and not a welders welds. The chassis have like 17 gussets plus some tubing changes for the boat side.
Can Am's have 4 very important advantages on rzr. The stock wheel base comes more ideal. The suspension geometry is better and in performance driving (not what 95% of the assholes that own them think they do) the difference comes out. The 3rd cylinder make big power easy and reliable and lower COG. They are safer and faster at high speed in sketchy terrain.
To go further on power. 230hp will not even stress a Can Am's drive train. 255hp is not putting anything at risk for endurance racing - stock diffs, stock shafts, tranny, block, turbo, exhaust, all not an issue.... where in a rzr 190 horse is jeopardizing pretty much everything in the drive train front to back.
many of these guys run stock knuckles with no issues in a can am. CT just puts a bigger bearing retainer clip in I think.
I am in a riding group of a 100+ people now. The rzr's need constant maintenance and are not built well at all stock. You would have a tough time with a mostly stock rzr keeping up and not breaking. The driveshafts arnt even balanced in a rzr.
I am not building a KOH car, I am build a woods car... different things.