So I tried P&G for a tank. It increased my mileage about 2 MPG. (I do ~ 70%Hwy/30%City)Can't say I feel it's worth it considering1) As Doax noted, it's a major pita2) It's a great way to (removed) off other drivers (as you accel, slow, accel, slow etc.)3) clutch wear.Of course, as a side effect,...