You don't need them. Answer the question. Or do you really not understand how the SAE J300 classification works? We get it, you don't want to answer the question because you know it contradicts what you claimed.Post all the viscosity specs
A 5W-30 oil has to fall within the range of 9.3-12.5 cSt @ 100C with a minimum HTHS of 2.9 cP/mPa-s @ 150C using the SAE J300 classification. Doesn't matter if it's dexos1 or dexos2, all 5W-30 oils have to meet those specs/minimums. The 2.8 specs 5W-30 and is the factory fill. The dexos2 spec is based on the ACEA C3 spec which does go a step further and states that HTHS @ 150C has to be >= 3.5, but that is inconsequential in reality because you're not going to see 150C/302F oil temps with this engine, even if you run it at WOT until the oil temp stabilizes.
You claimed the 5w30 dexos1 oil was too thin for the 2.8 but refuse to point out which oil is the dexos2 oil among the 2 oils I listed, probably because you know I chose a dexos1 oil with a higher viscosity @ 100C and a higher pour point than the given dexos2 oil. The oil temp with the 2.8 is going to spend 99% of its time at or below 100C, the only time it will go higher (and even then not much higher) is when towing, so the statement that the 5w30 dexos1 oil is too thin for the 2.8 is pure nonsense on your part.
So, kindly take your condescending attitude and your misinformation elsewhere. Maybe pick up a book as well.