Ephios---I just sold my 04 Elantra. Very good car. I used PP in her when I got her at 72K miles. I did a Oil change at 75K miles with PP 5w-30. I did multiple oil changes every 5K miles. I just wanted to try Vavoline Syn, plus it was on sale one time, and it was ok. My MPG seemed to go down .5-1.0 MPG. It was ok but I think my car seemed happier with PP. It has had PP ever since. It has 95K miles on her now and is still in th efamily as I sold it to my in-laws that needed a car. I do all the maintence for both of us and I'll continue to use PP in it. I'm actually trying to decide on either M1 or PP for my Venza--VenzaTRD