I started using motorcraft 5w20 because is the one ford recomended for our cars, and I heard is the one to use for break in period. Ofcourse I didnt buy it in the dealer since it was $7.95 a bottle, what a rip off. I found it in Autozone the exact same bottle for $1.79 a bottle, Also Wallmart sells it even cheaper for $1.4X the bottle. But I would like to switch to synthetic, I heard that Mobil 1 is very good, but which grade? is Mobil 1 synthetic 5w30 the one to use? and every how many miles should I do the oil change. I like to go to the strip at least once a month, and run my engine healthy.