The Cobra Engineering adapter is to fit a '07-'14 Shelby GT500 blower into a Terminator. So if the Roush blower you're looking at is from a Coyote 5.0 it's not going to work. Unless he has came up with an adapter specifically for that which pretty sure he has not! If it's a 2007-2014 Shelby GT500 blower then it's doable but not just a bolt on affair. You'll have to figure a number of things out as mentioned.
Good luck!
Ken
Good luck!
Ken