are your front kingpins black or polished? If not, break out the dremel… polished king pins work 100% better. My first Z (pre dremel purchase) i just used 1000 grit sand paper (or finest you can get your hands on) to rub them down. Works well, but not as well as polishing them. you may have to open up the holes in the knuckles where they go onto the king pins, but usually not necessary. When your front end is apart put a king pin through the knuckle hole (after polishing the kingpins) and if it still binds a bit, you may want to run a little drill bit through the knuckles to open the hole. Check bit sizes before doing this; you dont want to have too big a hole in them. Hope this helps… as for the diff, looks the same as the Kyosho one. Should’nt be too bad, in fact a definate improvement over stock spider gear diff
