Don't buy it for "better" gas mileage on the highway no matter if you go with an 04 or 05/06. It is ONLY better if you baby it in 6th gear all the time and lets be honest, how often do you think you will baby it? If you buy a GTO and baby it just to get 30mpg on the highway then go buy something else.
As others have said though, wait and go with an 05. Night and day difference.
2001 Volvo S40-Perrin MBC@ 11psi, EST intake, 35% tint, still slow
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