OK...I know that the topic of motor oil and what's best has been nearly beat to death but in my search I didn't find the exact info I was looking for so I thought I'd create one more thread on the subject. I have a few questions: - Standard oil life for conventional oil is 3k miles. What's th standard for synthetic? - Does my oil life indicator on my newer chevy truck (2007 Silverado) actually detect contaminates in my oil or does it dwindle down over a 3k mile span? The owner's manual gives the impression that there is a mechanism that measures constiminates rather than giving a percentage based on miles driven. - I've had Royal Purple synthetic motor oil hyped to me alonf with the new Green Earth Technologies (GET) Advanced Synthetic line. Anyone have any feedback on either? I like the idea of buying any oil made from resources here in the USA like with GET. - Can I really see improved fuel economy from going to synthetic from conventional? Thanks in advance for your responses. Any other thoughts on conventional vs. Synthetic motor oils are welcome as well. Thanks guys.