[Dafni]

If you can choose, go for a 5mm shaft. The hardened 1/8 shafts of the Lehner motors should also work well, I was told. But for Feigao's Nemesis, go 5mm.

Back in the days when I bought my TF, I got the helical ringgear and pinion from Tower. But I think Kyosho has an independent supplier in the states now. Maybe Mike can help you.

DAF