i agree with you on that last bit but i think a good modded zen will out perform a qd 25 ,the power to weight ratio would be a factor id think.i know dave marles zen 7 (7.3hp)beat all qd 25 and 35 powered boats by over 4 laps in one of the biggest races in europe a cpl of years ago and those guys are very serrious racers by all accounts.