When I drove 100 miles a day and wife was at 60 just for work fuel mileage was a big issue. I became somewhat anal about keeping track of it on both vehicles. Tire pressure was another. Saving money on tires at today's prices if you drive a lot is right there with MPG. Best ever on a set of tires--97,000. S-10 extended cab. Spending money on improving mpg is all about doing the math. How many miles do you have to drive to recoup 200 dollars spent to get 3 tenths mpg improvement? Chances are you will never get your money back unless you drive a shit ton of miles. If you are in the mpg ball park of what other people are getting then that is all there is. If you are on the low side--- things like a worn o2 sensor or thermostat that opens too soon could be an issue. As far as why this 2 stroke oil thing works for some people in my opinion is the benefit of reduced friction. Ever try turning an engine over even without the spark plugs? Add some premium lubrication to the cylinders and more of the power made goes to the crank instead of moving the pistons up and down. The result would be better mpg. To answer your question---I used Pennzoil. As long as it is tc-w3 it shouldn't matter. I did try and meter it closely but not get anal about it. Easiest way I found was a marvel mystery bottle. Long neck and is marked in oz's. Give it a try. Any gains at all from 20 bucks spent may be worth it. Does reduced friction matter?