Markus,
	I have a camber compensator on my 1966.  It does improve handling 
on the street.  It is taken off when the bus is to be driven in the dirt.  
I put a rear sway bar on a 1964 beetle years ago.  It was ok for low 
speed, autocross style driving.  The beetle handled like a go kart.  It 
felt twitchy and all wrong at speed on the road.  Sway bars and camber 
compensators are doing different things with your rear syspension.  Try 
the camber compensator if you really want to see some small improvement.  
Don't bother if you drive in the dirt.  I don't think that rear sway bars 
are available for your 1966 any ways.  Gary Gibson