I just started using the Castrol 0W40 Edge synthetic oil in a 2006 Jeep Rubicon 4.0L I-6 ...Looks to be an ideal long mileage oil designed for BMW , VW , etc. A3/B4 oil which I plan to run 10K OCI's with a Fram Ultra oil filter . It's an interesting 0W40 oil - different than say the 0W40 M1 oil that has different specifications ... Your thoughts ?