i'm feelin your mathematics sir. but look at it this way:
$1000 in gas is 50 tanks of gas. a Ten gallon tank would last me a week maximum. there are 52 weeks in a year. Its paid for after one year, and from there i am seeing the money i saved by doing the modification. say i keep it for 5 more years from the moment i do the mod. thats 4 years worth of money i saved on gas, which over the course of 4 years and 208 tanks of gas could really add up to be a significant sum of money, which i used to buy groceries, car payments, house payments. etc.
Saving money is saving money. Even if i was gonna save less than 100 dollars (1 or 2 trips to the grocery) i'd still spend the time and money to do it. Its worth it.
2 free trips to the grocery for what. an hour or two to go to the store, buy the shit, build it, and put it in?
worth it man. if i told you right now for the rest of your life all you have to do is come mow my grass, water my plants, and trim the hedges once a week for two hours and i'd buy you all your groceries for as long as you did the work for me, YOU'D DO IT! Free fuckin groceries! for two hours! that you could have spent doing what? dickin around on CR talking to some punk ass with a V6 mustang? obviously free groceries are better.