Okey, enough reading for me. The more I read, The more confused i feel. It seems hard for me to digest those great posts in this forum. :-( This is my case: I have an '89 honda prelude with 199k miles on it. According to the service receipts i have, the first owner put 20w50 mobile drive clean after 105k miles. The 2nd owner took it over at 140k miles point and used only 10w30 whatever brand. It became my toy at 160k miles . So far i pour only GTX 10w30 into its engine. It runs good so far but engine noise becomes biger and biger. And it also burns oil like 1/4 qt per 1k miles. it turns on to be very dark after 2k miles. There're many good discussions related with my prelude case i believe. But again, i cannot draw a conclusion so far. :-( The following oils r highly recommended in recent discussion and also available in my area. which one is the best for my prelude? 1. GTX 10w30 2. GTX 20w50 3. or Chevron Supreme 10w30/20w50. 4. Chevron Delo 15w40. 4. Pennzoil HM 10w30. 5. Mobile 1 6. Pennzoil Syn. Price is not a big issue except Mobile 1. All others are among the same price range here. the promotional price of Pennzoil Syn is about $1.9/qt. Thanks for your reading.