2016 - First year issues. Smaller injectors, fuel pump, clutch issues, overheating, pretty long list. The least desirable year.
2017 - More power and Polaris address all the 1st year issues, new clutch, bigger injectors, bigger fuel pump, completely redesigned radiator and front end, variable speed cooling fan, new steering rack, triple piston brakes, new digital instrument cluster. All turbos this year has the Fox Internal Bypass shocks. Probably the best year non-dynamix turbo made.
2018 - Polaris felt the pressure from the market to lower the price of the rzr's, specifically the Turbo to make room for the new Dynamix model. So, they made the base Turbos cheaper. The base model Turbo gets regular 1k Walker Evans suspension. They introduced a Fox Edition (which is much like the 17 model), and the new Dynamix.
2019 - New front end design, with cool ascent lighting. Upgraded instruments and improved Ride Command. 2019 also has a new clutch cover with improved clutch cooling. Introduction of the Turbo S model for those that want 72" wide machine.