yea the right mesh is sooo important with these plastic gears...check the mesh at 90 degree intervals when u set it too - some of the gears arent quite round, if u see what i mean. mesh may be ok on one side of the spur, but just spin it round and check the other "sides".

dont forget the threadlock on engine mounts etc!!

cenracer1 - do u have the cen .16 in urs? if u put a bigger/pokier engine in then they are a bit more prone to stripping, not sure if its the extra power or more chassis flex, prob a combination of the 2, but unless my gears are spot on meshed and "round" then kicking into 2nd can strip the spur a bit too easily on occasion. just a thought to bare in mind if u go the .18/big block route. had no probs with the single speed setup and my .18 tho.