I know this is a older thread, but easily found on Google nonetheless, so I would only add this bit of info: If you're stock, or just have a cold air, etc. Just do it... The tune is awesome for daily driving and having some fun while you're at it. I have the RS air cleaner, the Ford calibration with included colder plugs and its a sweet setup, super easy to do and works like a charm Don't over think it. I still get 32+ mpg average on 93 octane, and it just feels much more natural than it did before. Rubber in 2, 3, even 4th occasionally. Plenty of power if yours is your main driver like mine is. In the future, I'll venture to say that with bigger intercooler, or exhaust mods, it would probably just make more of what its got, miles of smiles.