What are the differences between the FS and ESP 0W 40 Mobil oils. Is one better for a GDI over the other. TBN, noack? The ESP came out for the new Corvette spec, but I wasn't sure what the difference was to warrant a different 0w 40 from what they already have. I have a 6.2 GDI motor in my new 2018 Silverado which is basically the same motor with different cam , intake and other things. I would think a truck motor would be subject to harsher environment and running conditions just from the weight difference between the two vehicles let alone if any towing is done with the truck. I drained the factory fill 0 20 after the first 800 miles and have been running 5 30 Mobil EP. Seeing the new spec 0 40 for the Corvette has me wanting to use that during next oil change. Thoughts?