How much more gas much would I get if I added this to my truck? How much does it cost and where would I get one?

 

Why don't you check the Online Store right on this website? A lot of us did. I'm happy with my Airaid, I got a decent price, and the Lemere's sent it right away. I'm not particularly mechanically inclined, but installed it myself with NO problems (altho' having to cut the stock hoses was disconcerting at first). Personally, I'm still racking up tank-ups and miles to determine just how much of an MPG diff I'm getting.
Check this out too:
http://www.sportruck.com/howto/f150airaid/index.htm

 

What Sundog describes is replacing the air intake system and not just replacing the stock air filter with a K&N air filter. My questions would be as follows. What are the results of just simply replacing the stock air filter with a K&N air filter? Also, although simply replacing the air filter wouldn't void the warranty, would replacing the air intake system void the warranty?

 

No. It doesn't. Besides, you don't really "modify" the intake by installing an Airaid. All the stock connections and sensors are still there, and in the same order. All you're doing is adding a less-restrictive unit.