The 850 kit is a whole different animal than the 800 for turbo kits, don't base your decision on the 800 kits. The 2019 boondocks kit they really struggled with. Personally if I was going to buy a boondocks 850 turbo Id only get the new agility kit. Rode with a friend today who has an 850 with the agility kit and new boondocks clutching and it runs very good. My Khaos with a new silber kit is good. Ive run the 3, 5 and 7lb spring. There is a little hesitation between 5,000 and 6,000 feet elevation, but it runs very strong. Boost for boost, my silber runs pretty much the same as the boondocks agility on the 2020 polaris 850's. The main difference is the altitude compensator on the boondocks is quite nice. I run at 8500 to 10,500 feet so my elevation is a lot different than where you will run.