its one of those things where you must ask yourself do you wanna pay now or later ,the lasleeve sonic is pricey but look wha t you get ,the best designs and parts already incorporated but as good as it is out of box even the sonic kit has its design flaws espeically the bottom of the transfers not opening at BDC and the smallish poorly placed sub exhaust ports ,the vitos kit is basicly a chinese copy of a 72mm bore stock cylinder with way less volume and poor workmanship full of casting flaws overpour and tiny inferior port layout thats way wrong ,the cast pistons are only good for a short time like 50 hours or they can crack at the intake bridges im told they fixed this but i only heard this secondhand .its like anything if yo uwant the best it likely wont be the cheapest option .lucky for us most of these kits can al l be ported to run similar times and power output ..just some are more work to extract the potential and will require upgraded parts,alot of why yo udont see really fast ones is becuase most builders who port them dont do it right IMHO..they need reworked and not just improved on by shining up whats already there from the factory