OK, I've been using Mobil 1 15-50 in my S4 and I like it. I send my girlfriend out for the simple task of buying oil and K-Mart has 2 qts left. She goes to local FLAPS and gets "extended performance" 15-50 at a very high price. I send her back and they tell her that the "red cap" 15-50 is being replaced with the new stuff. Is that what is happening? Greg 94 S4