Castrol GTX
Pennzoil
Kendall GT-1 - I know this sounds crazy, but I love this oil even though I havn't run it in my car yet. I think blending a 50% group III blend oil, and pricing it LESS than other conventionals is a brillant move by C-P. I will be running it at some point, probably next winter....
Does anyone know the exact chemical difference in the two? I guess what got me curious,is that I have 1/2 a quart of M1 15W50 and 1/2 a quart of M1 15W50 Extended Performance here at my house (leftover from previous oil changes). The Extended Performance one feels a bit thicker.