For what it's worth, I just got rid of a vehicle with 359,000+ miles that I owned since it had 8,000 miles on it. For the first 300,000 I ran Mobil 1 and Exxon Superflo synthetic (when they used to make it). Around 300k miles, I switched over to Pennzoil Platinum. My OCIs were 6k to 7k the entire time. The car still ran just as good as new when I got rid of it. Honestly, if it wasn't a base model vehicle with no power options other than A/C, I would have held on to it.
Choose the synthetic oil that you consider to be your favorite or try a few (that meet your engine specs) and stick with the one your vehicle "likes" the most. What I mean by "likes the most" is one you notice a better behavior from such as reduced engine noise and increased smoothness.
My opinion is that any decent synthetic will get you to 300k as long as you keep the oil changed, use a good quality oil filter, ensure that your PCV system works normally and address any cooling system or fuel system issues immediately.
Choose the synthetic oil that you consider to be your favorite or try a few (that meet your engine specs) and stick with the one your vehicle "likes" the most. What I mean by "likes the most" is one you notice a better behavior from such as reduced engine noise and increased smoothness.
My opinion is that any decent synthetic will get you to 300k as long as you keep the oil changed, use a good quality oil filter, ensure that your PCV system works normally and address any cooling system or fuel system issues immediately.