Hey guys, My contract job will terminate this year and I am considering to become a shareride driver next year. After some number crunching, it seems the biggest cost is fuel and maintenance cost. There are people like me just use the existing car to take the job which is not always suitable to address those concerns. So I am doing some experiment and research to see if there's anyway to reduce some of the cost. First of all, need to learn the oil change myself and get a membership at Costco for tires But for European cars, you still need to go dealer services so they can plugin the computer for you. Second, I came across this after-market signal purifying product that claims to improve fuel economy for 15%~25%, so I went on and tried it out. The result wasn't as advertised but much better than I expected (10~14%). Is any of you would like to try mine? I just want to make sure it's not placebo, self-feeling or coincidence of that sort. If this thing works, it may potentially save me $800 a year if I drive 4k a month.