I traded my Hugger Orange SS with white leather for a 2013 Roush Stage 3 and I love it. Took it out this morning as a matter of fact. Great, great car. A blast to drive and really comfortable.
As far as warranty work goes, if you have a Roush dealer nearby, you're good to go. (I do, about 25 miles away.) If a Roush part goes, you bring it to them and then it gets repaired as normal. But, if a non-Roush part goes, you can bring it in into any Ford dealer for repairs. For example, a power window goes or the stereo goes, you can bring it to any Ford dealer for those warranty repairs.
I bought my Roush from Ray Skillman Ford in Indiana and was in touch with the performance manager there, whom was my go-to guy. Highly recommended.
Did I mention the car is a beast and fun to drive? lol
P.S. You can pm me if you have any more questions.