For the higher mileage Tacomas . . . has anyone here used Mobil 1 Synthetic for the life of their truck and if yes, do you notice big differences as far as engine wear/ high mileage. Just curious. I just bought my 99 in Oct. and started putting Mobil 1 in at 65,000 miles. Am wondering if it will be worth it every oil change considering the outlandish cost for that stuff.