I just purchased a 2008 Outback 2.5 XT Limited, 5-Speed manual with 50,000 miles on it and have a couple questions. The oil cap says semi-synthetic for the turbo but my friend suggests that I use full synthetic. The last thing I want to do is blow my turbo. Anyone have any opinions on what I should use? Also the manual states oil changes every 3,750 miles when the car is being driven in extreme conditions. After that is states anytime the turbo is being used it is considered an "extreme" condition. Again my friend states that i "should" be able to go 5,000 without any concern. I 've owned many different vehicles however this ismy first turbo and i want this car to last me a long time. Do I gamble on 5,000 or just suck it up and change the oil every 3,750. Thanks for the help.