Anyone use AMSOIL Synthetic Oil? I ordered some for my truck. Gonna be about $60 for oil and filter. According to AMSOIL, it will last 25,000 miles guaranteed. I am in the automotive business and have talked to several people who say it is a very reliable oil and a very reputable company. I think I may do about 15,000 on the first oil change and cut the filter open and see whats inside. If all looks well, I am going to go on the 25,000 mile schedule.