Tuning a 2011 Mustang 5.0?

I want to buy a Steeda Cold Air Intake but the website says that it is tune required and will not work without one. I know that it would void my warranty if i got a sct remote tuner and programmed the tune the company sent me. But if i put the stock tune back in before I took the car to the dealer would the dealer find out that I had previosuly installed another tune into the cars computer? Also would the tune be harmful to my engine and is it really true that the intake wont work without the tuner? Thanks alot