save your money, the theory that synthetic oil is better is based on the molecules are smaller, so there is more of them. I thought about this question, keep in mind that many companies make bogus claims to sell crap. if this molecule idea were so good as to provide more friction free surface, then as soon as you put it in your car the idle should change. The reason being it takes energy for something to turn itself, if it moves more freely it should idle higher. The only product I ever found that changed the idle is prolong. But sadly this was only true while the oil was new, and after a little wear and tear, idle returned to normal. I tried different brands of oil several brands of synthetics, and the only difference I noticed is I paid a lot more for the synthetic. it does not stay cleaner longer, I am picky about my oil and when the engine oil is no longer clear (when I can no longer read the marks on my dipstick, through the oil, I change it.) synthetic gets dark just like regular oil and it gets dirty just like regular oil, and you pay 3 times as much as regular oil.
clean fresh oil is the best thing for your engine, a clean air filter, and a good quality fuel keeps the inside of the engine clean and it runs its best like that. save your money, wal marts house brand of oil works as good as anything else out there.