Quote Originally Posted by telyt
This is not correct. They are different designs and made on different assembly lines on different continents.

As for the original question, the R4 is not considered one of the more reliable Leica reflex bodies. I would suggest the R5 or newer including the R-E instead.
The R4 had the reputation for not being the most reliable camera. The good news is that after all these years, the bad ones will have sorted themselves from the working ones by now!:-) I'm not really sure where the idea that the Leica and Zeiss lenses were made on the same assembly line, I've never heard of that before. It's true that leica does not make it's own glass, and I'm sure they buy a bunch from Schott, but that's as close as I've ever heard of them getting. I guess the Kyocera manufactured lenses could be an oblique connection, but that's really stretching things. The new 50mm f1.4 from Leica is supposed to be the best 50mm f1.4 ever made when shooting wide open. I do lust after it in the M line, but I really can't justify the price when so many 50mm lenses are so good as it is. Of course as a Leica owner, you'd think I'd be pretty good at justifying the unjustifiable by now:-)