I noticed that some here are changing from the recommended 5w30 wt. oil for their vehicle. Many have fallen in love with the 5w20's and say it is better. Many (with higher mileage vehicles, maybe) say they are moving up to 10w30 oils. Is 5w30 not a good oil (shears more) compared to the other two. What are the pros and cons of moving away from your owners manual recommendation to one of the others. In my case, my engine is running good on 5w30 at 110,000, but no UOA's to compare anything. It leaks a little and I am thinking about a high milage 10W30 oil. Thank you.