Those certifications don't really mean that much, its basically licensing for oil, manufacturers pay GM to be certified as Dexos. Since our turbos are ball bearing based and are lubricated from oil, the extra grade and better shear protection that's formulated into oils such as Rotella T6 and Motul's Fully Synthetic X-Cess, can benefit long term performance. I've owned 1.8T VW's for years now and I won't put anything lesser in them. Those engines have been known to coke oil, and the extra heat tolerance that 5W-40 brings to the table is invaluable.
But honestly, this isn't the place to discuss oils. Bobistheoilguy has several 1.4T oil analysis' from Cruze owners. If you want to read on what the best grade is for your engine. I suggest hopping over to them.
I personally use nothing but Motul's X-Cess on Amazon. And if your oil change intervals are below 5000 miles, the grade of your oil won't really matter as long as it is fully synthetic