did somebody tried this new kit sold by beedspeed ??

are you talking about the standard type kit with a lager bore piston? frankly, i don't really see the point. the standard cylinder isn't the lustiest performer, but that's hardly because it lacks capacity but because the whole layout is rather dodgy, and that does not really change once you overbore it. if you want bulletproof reliability leave it standard and save money by using the cylinder your engine came with when it left the factory, if performance is what you're after go for a proper kit such as malossi or polini.