That is not completely true. Some people have issues with trying to tune a Roush tuned car but it can be done. The problem comes in (as I understand it) as Roush has the computer "locked" (someone correct me if I am wrong) and the new tuner (Bama, Steeda) has to send a factory tune to the car first before you can install a new custom tune.
Again I have no interaction with Roush tunes, this is just my limited understand on what I have read. There is a link on my Facebook about it. Let me see if I can find it....
Here it is - http://www.moddedmustangs.com/forums...nightmare.html