So I plan to DD my 2017 Z51 year round from 10-20 degrees to 95 degrees. I can use DEXOS 5w30 M1 but I would like to use readily available 0w 40 like M1 FS euro spec from Walmart. I also have 10 qts leftover M1 5w40 from earlier this year I’d like to use up. I have no warranty and will do yearly oil change at 4-5k miles, maybe a little more some years. No track duty. I have zero inclination to chase down M1 supercar oil for the extra money. All considered, should it really matter using euro spec oil versus latest of several DEXOS certifications that have evolved? The 40w might get a little less mpg, but cold start if of more concern to me as well as longevity. It’s a 10k mile car now. Should supposed emissions equipment benefits make a difference as long as the car burns little to no oil? Would a high quality 0w30 be better ever for my situation? I understand GM engineers create oil specs to be met, and that those specs change over time, but I’m not as interested in a certain certification as much as what should or shouldn’t work fine for my situation. Thanks for helping.