I had a 700 Rhino in the 'sued by everyone' days and Yamaha's agreement was to add 2" spacers to the rear and delete the sway bar. Dealer was not supposed to give you back your sway bar but mine knew me and my machine and I never put it back on anyway. I ran stock aluminum rims (6" fr-7.5"rr same as Honda) with 25x10x12 Baja Cross's and Progressive shocks. When dialed in shocks helped but the 2" in the rear with no bar was huge difference in stability. Narrower front rims kept bead out of trouble. I had a set of 1" spacers laying around and put them on the front with not much noticeable difference except I ate more flying filth! This was a 60 plus mph machine. Don't know 'percentage' of benefit but rear spacers probably do most of the work. I'm going to put 2" on the back with 28x10x12 Blackwater radials this summer on the P5 I just picked up and see how that works.