They are rattly from new, it's just the way the MuliAir unit works..
The correct oil, as described in the service handbook, is very important.
Best practice to change it a bit more often, like every 6-7000 mls, incl. filter.
Often overlooked, but VERY important at these somewhat higher milages, is to change the MultiAir strainer/filter, it's NOT in the sevice schedule, but should be changed at every ~30.000mls.
Engine will last forever.