Its my understanding that mobil one isn’t really a ‘true’ synthetic anymore. All oils are formulated with some sort of fairly standard base stock. Mobil one is now on a group III base stock which is a further refined mineral oil. There is some FTC law that still allows it to be called synthetic. Its still a good oil but not technically synthetic.
Amsoil and older formulations of mobil one are true synthetics With PAO or group IV bases. Redline is a group V ester base.
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I Use amsoil in my car and leave it for about 10k miles…95% of my driving is extremely easy. They claim its good to 25k but that seems a little outrageous.