All beamers young and old seem to have that "buzz", especially at that low to mid 60mph range. Even the K100's have it.
It wasn't until BMW spent some time going back to the drawring board and came up with the K1200's did they finally get it right.
I never did get used to having my finger tips and feet go numb.
You should test ride a K1200RS, but be warned, it'll spoil you forever...