I doubt if anyone other than the govt is going to put a detent spring in your car. So...if you install one yourself...you've demonstrated the INTENTION of saving gas?
I'd really like to be driving a fast car and not worry about wasting fuel...but being cheap and looking a bit into the future...I'm adjusting.
I like the G forces as much as anyone...but it eventually seems pointless to see how fast you can get from A to B...when there is no real reason for it....except for the RAT RACE.
My advice? Quit racing with the rats...you just ain't gonna win.