dt 125 x powervale motor

hi there, i'm thinking of buying a dt125 x the super moto version, just wondering if the engine has chaned much from the older type,

i used to own a 1988 dt125r so i'm familier with the power valve, i know there is a servo motor kit to make better use of the power, will this kit fit on the newer engines, eg 2005

i can remember with the powervalve closed it was responsive down low but lacked top end pull, but open there was a big flat spot in the middle of the rev range

any advice appreciated

cheers, nick