I run the OFT kit on my '16 after I bent the stock steering system (which I didn't like anyways) and it has been awesome! Would never think about going back.
I cut the stock post because it was bent like I said, but yes on a fixed post sled you have to get the piece from a 4 stroke or rr to run this post. It's stronger, less complicated and makes the sled handle so much better once you get used to the change.
OFT's kit doesn't change the bottom cross member at all so if it breaks, it would've pure stock as well. C3's kit comes with a weak replacement which is what people have been breaking and replacing with 3/4" aluminum round stock bent to fit I believe.
I think you can even get another half inch on top of oft's kit without causing issue with the stock crossmember, I am 6'2 and I think just an extra tiny bit forward with 4" rise and boondocker 2" bars would be perfect.
You WILL NOT regret getting it, believe me.
Oh side bonus OFT comes with nice billet parts that won't cause issue like the stock crap.