Not to be controversial but while examining the Castrol synthetic oils - nothing jumps out at me for being a good value (versus M1 & PP) EXCEPT the 0W40 . I tried the Edge 5W30 in a 4.2L I-6 Trailblazer and experienced oil consumption and an oil that turned black early (vehicle has had nothing but synthetic M1 & PP for 50K miles relying on oil life monitor changed at 20%) . Now an oil turning black early may / may not mean anything negative - I'm just not sure what the over priced hype is for Castrol Edge is for all but (maybe) the 0W40 as compared to M1 , PP & even Valvoline ... Your thoughts ?