Fast by Ferracci still has them available:
Easy answer is match donor bike to donor engine, i.e. keep 2-phase bikes 2-phase. Granted if you have mad skills and time you can upgrade a 2-phase to a 3-phase but I prefer not trying to ice-skate uphill... it's very tiring.Right... the three stage vs. two stage correct? There is no simple way around it or easy way to swap one for the other?