Mobil1 ESP X2 is also DexosD rated. Not cheap, ~$13/qt.
I went to pick up a couple quarts, as I checked my oil, nothing was on the dipstick, and found the local carquest parts store stocked the GM part number for $5.45/qt. It wasn't listed in their inventory when I checked online.
1 quart raised the oil level to the mid point on the dipstick. I think they could have done a better job with that. You should have some indication before it just disappears, like a quart low is the bottom of the tab...