I've ran all the HM oils available at my local wally world. I definitely noticed more leaks with mobil 1 ep HM and pennzoil plat HM (but also smoother quieter engines). switched to HM blends only after realizing all the oem oils my rides come with are blends (1996 to 2011-6 different vehicles). Several mechanic friends of mine prefer castrol so i use the gtx green bottle. definitely noticed fewer/smaller leaks with that and valvoline red bottle. Always used 10 30 at 3 k intervals.