I'm still using Castrol Syntec, but the 0w30 'europeon formula' since it's supposed to be a 'group 4' synthetic. Used 10w30 syntec up til a couple years ago. Since i change my oil so often (try to stay close to 2500 miles each time) I suppose it doesn't really matter. Have only used the Mobil 1 filter too. The Mobil M-105 filter fits the VX and is a little longer than the one originally spec'd for it, the M-104. As expensive as oil can be, it's still cheap in mho. Scott