Proper connection of a non-BMW provided GPS receiver to specific BMW plug

[Grumpy Goat]

The MotoPump will be a sturdier mount because it has fewer parts, less weight, and more rigid mount. 

I am [casually] looking for a lockable mounting solution for my Nav VI that I can use on my Tiger, which has the Garmin windshield mount car adapter as a basis. I do not like the lockable one from Touratech.

I like the idea of the MotoPumps adapter (for the reasons you mentioned) but that is only for GPS units like the XT/XT2 which have the AMPS type connector and not the Nav IV/V/VI type connector.