What would be some of the better oil and filter combinations for a Chevy 2500HD w/ the 6.0L engine driven in moderate to heavy driving conditions in the South? I don't plan on extending my drains past the Chevy computer or 7,500 miles. I don't guess a regular filter would work much longer anyway? Would an engine like the 6.0L ever see any benefits from using a specialty synthetic like a Redline, etc? GM recommends 5W-30. Thanks.