I own a 2006 Ridgeline with 66,000 miles. I want to change over to synthetic oil. What are some of the brands and viscosities being used out there? Is there anything I need to do special when switching over or just change the filter and fill with synthetic? What about mileage between changes? I usually change the synthetic oil in my daughter's BMW 325i at 8,500 miles but have heard of others going 10,000 - 12,000 miles.