flex coupling from PYI

[Fulvio]

I have done my homework and researched the site, but I don't see any references to the flexible couplings sold by PYI Inc:

R & D Fkexible Shaft Coupling

It seems many here have gone with the Bullflex, Federal, et al.  Is the R&D (PYI) one what you would call a "drive-saver", rather than an actual flexible coupling?

A friend of mine installed it on an Alberg 35 (after having it repowered with our very own Universal M25XP), and was very happy.

While on the subject, what is the model of the Hurth transmission an 89 C34 like mine would have?  There are no labels on it, other than the manufacturer's name.  (the engine is the M25XP)
Am I correct in assuming that the transmission provides a 2:1 reduction?

Thanks all!