whokilledthe jams, all I have to say on that subject is that my MPG included leaving thug country, driving through redneck country, (yeah, we got 'em in Cali too!) and ending up in rich, white, and self-satisfied Santa Barbara. None of which affected my mileage, but there you go. ;-)
I think the thing that gets me better mileage, if it is true that cold air kit and bigger exhaust give me worse mileage, (which I have to really look into) is that the car has been lowered 1 3/4". So my roof is that much lower and I have that much less air going under the bottom of my car. I am not really doing anything beyond P+G, drafting semis, max tire inflation, and going slower (50-70 avg) and very rarely EOC, and I'm just starting at this. Lower the car! Just be careful with curbs and parallel parking.