1. 2011 GMC Terrain 3.0L V6 LFW build date 8/13/2010, currently has 84K miles. 2. Owners manual says dexos only, but indicates if dexos is unavailable to use oil with "API Starburst symbol and of SAE 5W-30". Owners Manual. 3. Michigan lower peninsula, gets cold (0 degrees F, sometimes negative). 4. Easy and slow mostly, since it's the wife's car; when I take it about once a month and it's warmed up, I drive it harder/faster to increase oil pressure, etc. 5. Short trip to work (less than 10 mins); we do take it on 300-500 mile road trips once or twice a year 6. No known mechanical problems, always had dealer serviced oil changes according to the OLM. I found some early blackstone analysis on the forum: Oil Analysis 1 Oil Analysis 2 My concerns are around this being an early DI engine, the mostly short trips and temperature fluctuation/cold winter we have in Michigan. I believe the engine/powertrain warranty has expired (I'm not concerned about dexos) and I've heard good things on this forum about 0w40 from Castrol and M1. But the M1 site recommends 5W-30's. I already buy Catrol 0w40 (LL-01) from walmart for the BMW, but I only change that oil every 15-16K, so having another oil for these short OCI's isn't a huge deal. I've heard the ZDDP content of the Castrol is good for the BMW, but may not be beneficial for this engine. I'd prefer to go full synthetic, but I'm open to any suggestions (and especially experience of those who have same/similar engine), thanks!