Second oil change for this beast at ~15K (do it ~7.5K/when it makes sense for warranty/recalls/campaigns etc. - only drive ~12K/year). The 3.6 VR6 is known to be fuel-diluter so this seems in-line with what I've read. Low viscosity is interesting, not sure there. Dealer should be/confirmed use of Castrol OE 5W40. I will likely DIY with LiquiMoly once we get to a point that I don't need any of the above at the dealer which should be soon I hope!