Installed my controlled Kaos today, have only about 30 miles on it, mainly from stopped going 1-2 miles, stopping going .5- 1 mile, over and over. With out testing equipment to give specific data, I will say the bike is a little zippier, not a night and day difference, just a tad bit more. I rode it with and without a helmet, it is quieter without a helmet (in my case a modular that is fully buttoned up). With the helmet on and buttoned up it seemed a lot louder. Made no sense to me, thinking the helmet would muffle sound but in fact it enhances the sound.
RLS packed it well, my box was damaged (hole in it), but there was so much bubble wrap around it there were no issues.
I came up with a better technique to putting those springs on. I still use the puller that he sent, but I used a ratchet strap with two loops. One end went around the puller's T handle, and the other was looped for my foot. I pulled with my foot and pressed it in with my hand. Legs are stronger anyway, and my physical size limited my ability to reach in and put the spring in place while pulling (weird angles and a rail in the way). Worked like a charm. Thought I'd pass it along. I experimented with several techniques, lifting the bike even, and found that the strap and puller with about 3 pump ups from my lift made it pretty easy. I have more than enough upper body strength to pull it, it was just the positioning and angle that made it odd. FWIW. Next mod is the lights, then maybe some performance stuff.