which is better for New emaxx? 1 motor or 2?

If planning to use a single Feigao 8L (5mm shaft) in a NEW E-MAXX 3905 -

Do you need an extended pinion? -

If so , where are they available?

[lincpimp]

Not really, a std 5mm bore 32p pinion form mike here will do ak. The 5mm shaft alowws the pinion to be placed farther out on the shaft without damage to the shaft during use.