This is a disappointing read. Does anyone know if there has been a specific redesign for the synchros, and if so, when it went into effect?
FWIW, other manufacturers have encountered this problem. They discovered that the fluid used in the tranny can help. So, while I'm sure it is not an approved fluid for BMWs, something like GM Friction Modified Synchromesh or the "reformulated" Honda tranny fluid may clear this problem right up. Both manufacturers had problems with synchros and both came out with "new" tranny fluids:
http://www.amazon.com/88900399-Synch.../dp/B00BK7M2VW
http://www.amazon.com/Genuine-Honda-.../dp/B001IWL1O8
The friction modified fluids are actually LESS slippery than typical transmission oils. Thus, the synchro can grab sooner and get up to speed faster. I had the second gear grind in my Honda S2000. The different fluid pretty much made it go away.