I have not used any synthetics before and I searched for a post on this, but no luck... 1. What kind of vehicle you have 2010 Dodge Ram 2WD hemi 5.7 20,000 miles. 2. What your owner's manual says -- not just viscosity, but certifications (look for acronyms like API SM, ILSAC GF-4, etc.) and change intervals as well API Certified SAE 5W-20 Engine Oil, meeting the requirements of Chrysler Material Standard MS-6395 3. Where you live Richmond, TX (near Houston) 4. How you drive (easy? hard? fast? slow?)mostly easy and not more than 5mph over the limit. 5. What your daily drive is like (short trips? long trips? city? highway?) 30 miles rt to the office each day some stop n go on freeway. occasional trips of 250mi rt or so. Tow a 6000# boat almost every weekend in the summer (may to sept) 6. Whether your car has any known problems, No problems. Looking for best protection/gas mileage. I wont do long drain intervals, too old school, not more than 5-6k mi or so. Not too concerned about $, but also consider value for $ spent. Thanks to all for your help.