The alternate is adding an S/C! The reason the desiels get better milage is that it makes the turbos more efficient and power is made earlier so you don't need as much skinny pedal. I assume this is true with all forced induction vehicles because I gained almost 3mpg when I added my Supercharger. My buddy with an S4 (BiTurboV6) gained 2 mpg when he got his chip. Though, I think it helps more with the torquey engines. All the engines listed are quite torquey.

 

True dat...turbos are great... I love mine on my F250. I want to put a larger exhaust on it to listen to the turbo whine like a jet.

 

gadgetonline.com has a right up and a dyno test of the CAI and on average the gains were about .5 hp.....moding the stock airbox gave alot more gain then that....