well, most folks will tell you it is a waste of money but I seem to feel a difference in some bikes and cars. I say, give it a couple of tanks with high grade and then go back to low grade for a tank and see if it makes a difference. Then after try a tank or so of mid grade, sometimes this can be similar to higher grade and sometimes feels the same as low grade. Give it a try and see if it is worth the money. I´m currently trying this on the 04 shadow I just bought.