30mpg at 80? that doesnt sound right. no disrespect, just saying that usually the mpg ratings of a car aren't at a speed of 80mph. and a 2004 rsx-s is rated at 31mpg - hwy. and considering were around 3500 - 4000 rpm at 80 in 6th..... i dunno, just my 2 cents. i mean, sure you may AVERAGE 30mpg on the whole TANK, but obviously mpg goes down, as speed & rpm's go up.