This might actually help you pick up a few tenths there Fuelly. Zoom on over and get yourself one!
I'm a pessimist, a skeptic; in my opinion if there was an actual (consistant / measurable) MPG improvement of several tenths then I believe ALL manufactures would be using a similar system; but even if it is true I would need to purchase alot of gas to pay for this $300 item (especially now that gas is at $1.65 /gal. - better yet is my diesel is now at $2.19).
My fuelly MPG have slowly been trending downward - but I blame it on two factors:
1. Several months ago I installed a full-time roof top cargo box, and
2. I'm no longer driving over open roadways (it's now mostly in town miles, w/ stoplights).
So even though I have my doubts if it puts a smile on your face then go for it. Incidentally, I prefer a quieter ride, not the howler you've introduced.
Lastly I suggest you retain/ provide the original parts come trade in time.