I think it made some difference in the low end to mid-range. My tires are 28” Sedona Rock-a-billy tires. Honestly not sure about top speed. I’ve hardly ever topped it out.
Super ATV told me this kit would turn up to a 30” tire well. I like the smoother engagement. I’m a little different in the RZR world. I do chores with mine also. I probably should’ve bought a General, but this was more acceptable price-wise.