[a.graham52]

your bringing up a lot of good thigns here. at the dealer i work at we do milage based service. at 100k we do plugs and wires, oil change tire rotation blah blah, trans flush, air filter change, fuel filter change (gm did away with fuel filters in '04, check and see if your car has one).

if you dont know when the last time your plugs and wires have been done then go ahead and do them.

tires: i have 16s" and at one point i ran 37psi. didnt help much in fuel pressure and made the car squirly. i now run 32-34. keep an eye on the tire tread, if its wearing in the middle more then the outsides then it has too much psi. to little psi and the outsides wear more.

alignment can effect millage and overall handinlg of your car

cai/wai. had both. buy the cai and you can easily convert it to wai. i live in main and durring the winter the cai was a POS and killed gas millage but i had power hahhaa. i run the wai for better millage (think of this: you get warming air into the engine (thinner air) and it requires less fuel to burn. get colder air into the engine (denser air) and it will require more fuel to burn resulting in less millage).

msd coils might help your engine be more efficent if you can get them for the eco???? i have an LA1 so i dontrealy pay attention to the 4bangers. need any help just keep posting. feel free to pm me with questions.