saving on gas in a cage

[dReWpY]

i am picking up a 1998 cherokee from a old college buddy, he says he is getting 20-22mpg but he does alot of highway

whats the consensis of the board is it worth putting on a free-er flowing exhuast, air filter, and chip in?

im looking for mpg, i have a fairly decent trip to class 4 days a week of atleast 50 miles round trip

so lets say i get 18 mpg (traffic in and around the town is bad)
55 miles per day
4 days a week
55x4=220 a week
220/18=12.222222 gallons a week
12.22222*3.60=43.99 dollars a week
175.99 a month in gas alone

i only make 800 a month
so if i can eek out some milage without going over board it might be worth it

if i get 2+mpg
it saves me 21 bucks a month
in a year the chip pays for itself if i pay retail