All you need to do is find out from your friend that used the 孖速 ....what was their 2nd pinion gear (tooth) and their 2nd gear spur (tooth)......then use that gearing on your motor (still single speed)...possible need a LOWER KW motor (if you have 2750, you might want 2450) to accomodate the low end punch...by calculation, there is NO WAY your car is slower then the other...unless they are using better lipo, better motor and better esc...