I was at Rio Bravo this past Saturday for open practice. There were quite a few Vet riders there, and I was talking to one of them I know casually. He has a 2013 250sx that he installed the 300 hundred kit on. He also said he had the carburetor taper bored, and did something to the exhaust valve, but don't recall exactly, a flywheel weight. He also said he runs a tall gear, but don't know what tooth it was. He knows I race a lot, and wanted me to take it for a test. First thing I noticed, was very little engine vibration. Bike was very tall with bar risers, lowered pegs, tall seat, longer shifter and sprung for his weight (250#), I'm 150 and it was rigid. I cruised it easy for a couple of laps, then begin to step it up. When I would roll on the throttle, it felt more like a 4-stroke than my quick crisp 250. There was no hit, just long a long hard pull against the tall gear, and a corner would sneak up on you quickly. I never really got it up to race speed, as I was not comfortable on the bike. The cockpit was setup for a big fellow but overall it had a little more grunt than my Sx. Nothing wrong with the mod, but don't think it is for me. Maybe if it was on my bike, I would think otherwise. Oh, and the bike was beautiful. It had every orange bling, cap, cover, lever, nipple, with seat scheme and plastic to match. Is there any longevity issue with these kits?