I was slightly concerned about how my Mobil 1 had thinned out to 6.98 cSt @100c last change even though wear metals looked good, so I decided to run Pennzoil with a similar OCI to give it a fair comparison, as my driving styles for each were virtually the same. The 4B11 looks like it took well to the Pennzoil, so I'll be sticking with it and extending my current fill of the PP 0W/20 to around 5,000mi like Blackstone has suggested and see where that gets me.