valvtronicdude on the 3 series forum had some information on the new lifter design:
The ticking noise you are hearing is the exhaust lifters intermit not getting 100% oil to them. by this i mean when it ticks it's getting oil just not 100% some is air. This will not damage the engine, for the lifters or (hva's hydraulic valve adjusters) are simply shocks for the valve when closing.
It is only the exhaust lifters, at the dealer they are replaced with updated style with new pn, they have stronger internal springs and larger oil delivery inlets.
New lifters were phased into production on later model 2009's they are staggered in the production ranges, the dealer will know what heads have updated from the factory and which require new lifters.
2002 E39 M5 / TiAg / Tubi Rumore / E60 SSK / Ultimate pedals / NCS Coding /