Well, so far-so good with the e3 spark plugs I put in my Ram about 3 weeks ago. Last weekend I install my JBA headers, and at last tankfull, I went from 18 to 20 MPG. Engine seems to be running smoother and throttle response has perked up too. Don't know which has more to do with the better MPG, but I'll keep running the #s at fill ups and letting ya'll know. So much can alter MPG I know.