After having difficulty finding the Mobil one dexos 2 oil I wanted I went to my Chevy Dealer and purchased the GM Dexos 2 oil from them. $10.72 per quart.
About the same price as other brands.
And from what they tell me Mobil 1 makes the GM Dexos 1 and 2 oils for them.
I do buy the AC Delco filters, there are some cheap "Junk" filters out there and I don't want them in my vehicles.
Now don't get me wrong there are some good after market filters also but you have to read the specs and micron ratings on them.