I have heard lots of you guys putting 5w40 in your jeep but I just can't get myself to put that "thick" stuff in my little 4 banger. I have been using mobil 1 but I am thinking of switching to Amsoil 10w30. I would love to put the rotella 5w40 in but it jsut doesn't seem right. My question is this, when you talk of extended drain intervals do you use the same filter for the entire 6k-10k?