Picked up some Long Life 15W40 to use in the wife's Outback this summer. Have been using the Pennzoil HM 10W30 the last few changes. Have been reading a lot of infor on the Long Life here and how the Diesel Oils keep the engines cleaner. The car is a 2.5L and has about 116K on the clock. The manual specs up to a 10w40 in summer. I think the 15W40 will work well in this application. Any Opinions?