Has anyone done the VANOS piston rebuild on an E60(61) N52 engine? I haven't yet taken the valve cover off - want to address a few oil leaks - but thought I'd do the VANOS while I'm in there. Car has 140k miles on it, so likely due for it...

Has anyone ever done this job on this car? from photos I've seen, it does look like the vanos units are as accessible/dis-assemble-able as they are on other 6 cylinder motors.

Any opinions? Direct experience? Advice?