re: which is the best kit?
I have looked into actually importing a container of these motors and have been told that as far as the engine goes, they are mostly the same. There may be slight variances that keep some parts from being interchangeable but that is all because of manufacturing processes, not performance reasons. When the motors hit the docks from China there is very little difference. The parts in the kit other than the motor is where the difference comes in. Carb's, chain tensioner, grips/kill switch, chain, fuel tank size, tool kit, extra bolts/plugs/motor mounts, installation instructions/support, shipping time, etc. are where the major differences come in. These can all vary significantly. NT carb or CNS carb., roller bearing or non-bearing tensioner are examples. The manufacturing in china is government controlled. They don't like to make a variety of motors when one is simpler from inventory control or parts acquisition viewpoint.