my gf got a new to her cavalier and she is get 25 to 32 mpg depending on how is driving well i have dune the normal mod the air box to let more air in k&n drop in air filter tire pressure i was thicking maybe a exaust does some one here have other idears or agree with me

 

I have a BOMZ cold air intake that I put in along with a catback exaust and I am getting 3-5 more mpg as long as I'm not redlining it. You can also look into putting in lighter parts(i.e. hoods, fenders) or even taking out some things that you don't need. The lighter the vehicle the less fuel to push it down the road.