So the oil extractor should be delivered any day now and the new GMC (see sig) is about due for it's 2nd oil change, which *will* not be occurring the dealership (even though free of charge) after the over-fill debacle resulting from their incompetence with the first "free" oil change. I'm considering using Supertech 0W20 dexos gen 2 SN+ full synthetic. I know it's a group III based synthetic, not concerned. Carries the right specs and priced right, blended by Warren who's reputable. About the extractor. I use them (replacing worn out one) to extract the majority of the oil so that when I pull the drain plug it's not as much of a gusher. The more subdued flow that exits the sump after a full extraction is just the dregs the extractor could not completely remove and it usually trickles. Short version: Dexos licensed oil that meets specs, no mess, and owner performed "BITOG" precision.