What is this Aktiv thing, i've heard abut it before too?
i'm still lookign to fidn this aktiv thing, spotted the roller switch for volume already..
ever seen one pop up anywhere?
I have seen the volume control switches that go in the dash facia, if thats what you mean?
yes the MK2 does have speed sensitive volume adjustment, thats what the yellow/white wire on the stero plug is for. Its hardly ever wired in though, and certanly modern head units do not make use of this wire.
I have a feeling it might have been used on MK2s fitted with the aktiv system 
I knew i'd heard of it then, if you say it, then it must be right!! So how does it work then?!