Ok so I know that the s3 and s4 gears are apparently supposed to help the car stay in a lower gear for longer. My question is, when do i use s3, and when do i use s4? I don't know which is going to help me in a situation..i was told that the gears help with when you are going down a hill, or passing a car, but they lower your gas mileage....all in all, i'm just confused...but i hate to not use them if they are actually going to be helpful in some way.