2001 Chevy Tahoe with the 5.3L. Since the first oil change when new I have used a full syn oil like Amsoil, Redline or PP......I even used Royal Purple once. Last week, at 145,000 miles, I put in Amsoil 5W-30 and the EA oil filter that Amsoil recommends. I sell real estate in the metro Atlanta area so I drive a fair amount in southern heat and Atlanta traffic. I usually change the oil at 10,000 miles but this time I want to push it to 20,000 miles. Since I am using the EA filter - with a FilterMag - can I go the extra miles? I know the bottle says the oil is good for 25,000 miles or one year but is this marketing or truth? Anyone out there actually run Amsoil the full 25,000 miles with the same EA filter? My Amsoil direct jobber that I buy from says the EA filter is fantastic and that going the 20,000 miles is nothing for that oil / filter combo. Any input is appreciated.