ask any builder who knows the fundamentals of 2stroke performance....the blaster's stock head design is completely wrong. it actually inhibits the motor from functioning properly.
the squish band and angle is all wrong. the motor has so much more potential for compression and, subsequently, bottom end power than the stock head design gives it.
i always recommend kennedy_power for any engine mods. the guy knows what he's talking about, he's done tons of research and tried all kindsa head designs that he's dyno'd in ordered to get max head power.
i'd say it's more than worth the money.