I have the PDS for SP rated Supertech 5w-30 Full synthetic, it's virtually identical to the SN Plus version
From looking at spider charts, Dexos1 Gen2 has been equal to ILSAC GF-6/API SP
https://www.oronite.com/about/news/GM-dexos1gen3.aspx
If you're looking to restock, you might as well wait until D1G3