As mentioned above, I want to switch over to the new Mobil 1 0w40 ESP, however I'm now curious if GM would allow other dexos2 oils under the warranty? For example, there are two options I could consider, one is Mobil 1 ESP 5w30 and the other is Pennzoil Platinum Euro L 5w30. Both will have an HTHS of above 3.5 (I've read on here that the Pennzoil might actually be 3.68!) The problem with M1 0w40 ESP is that it's reported that it's not hitting retail outlets until the end of summer, and someone that spoke to a Mobil 1 rep was told it's unlikely to be sold in Walmart due to it's limited market. For that reason I'm also thinking it won't be sold in the 5 quart jugs but in single bottles. So it could be quite pricey, but PP Euro L 5w30 is currently sold at Walmart in 5qt jugs for $27.76 and has been $22 recently too. So now I'm wrestling with the idea of these other options. I'm sure in the future there will be more 0w40s available that are dexos2 certified as well.