2008 R320 CDI Update
 

Well,

The car remains completely stock at this point and no matter what I do I can not break the 1000 km range on the tank. I've been really close a couple times at 950 km but that is it.

I need to look for a set of winter tires for it and would consider upgrading the dual air intake filters to something other than stock as they take a bloody hour to remove with all the parts you have to take off to get at them.

I'm also looking for a Canadian supplier of cabin, oil and fuel filters as the dealership is $$$$. Anyone get that stuff?

whats the point of two air filters

Because it is a V6 there is 1 intake and air filter per side.

i get it. all this new fancy stuff