I've been using 5W-40 Rotella synthetic in all my vehicles for years. I recently bought a Subaru outback that calls for 5W-30, and I've been recommended to use even 5W-20. So, I get the feeling that Rotella is a bit too thick for my Subie. Anyone have a recommendation for a full synthetic 5W-30 or 10W-30 that will live up to the standard of Rotella? Something less than $20/gallon preferably.