I started hating my Saturn when it was getting about 20 mpg on the highway. I started loving it when I did a major tune up, added some modifications, and am getting about 53 mpg on the highway (doing 55 mph -- only 47 at 65 mph).
Not bad for a car with over 100,000 miles on it. Also, I can say I have an awesome FE car that is made in the USA!
Hot Air Intake
IAT sensor mod on switch
Manual cooling fan override
K&N Air Filter
Partial grill block
Oil catch can
Synthetic oil and transmission oil
Increase spark plug gap
Small aero mods on front bumper
Removal of side mirror (if I can find a cover)
Partial or full belly pan