so are you saying that because vw spent so much money developing cylinder heads that they can't be improved? their breif would have been cofined to a budget and the confines of mass production otherwise all the parts would have been hand made. the cylinder heads would have come out of the factory ported and polished. Virtually everything on a mass produced engine can be improved. believe 
for people who have opened up their engines this is very strange. has anyone actually looked at the cams?
the tappet does not go on and off like a switch. the cam has a shape that starts opening the tappet until it is fully open. it then starts closing the tappet.
this open and close is not a full on and off, its a gradual on and then a gradual off. so the weight of the tappet plays no part in it. the open and close is dictated by the rotation of the cam.
the idea that you want to balance the tappets is very odd. they hardly weigh anything in the first place. plus they are machine tooled which will have incredibly tight tolerances. the reason you balance piston heads though is because they are cast and then machine tooled.
a mass produced engine is a compromise, thats why you can improve it. however, for every change you make there is a counter action.
cause and effect.
