Good luck in the upgrade to a Shaker system, but be mindful up front with the knowledge that you're heading into a real cluster trying to add these amps, subs, etc. The Shaker systems have upgraded wiring harness and I believe that my 07 Shaker 500 has an upgraded alternator from the factory. My current Shaker Pro head unit has Sync and a bunch of other stuff integrated into the head unit and tied into the steering wheel controls. I know guys who have tried this and just torched their sound systems, from blown fuses to door panel rattles so loud you could hear them entering the neighbor. Overall, these Shaker head units have a lot going on in them.
2014 Mustang GT Coupe Premium. Options include: California Special package, comfort package, navigation, glass roof, shaker pro system, 3.73 ratio limited slip axle, GT front grill/fogs, MGW race spec shifter, BBK X-Pipe, Corsa GT500 Quad Sport axle-back, Ford Racing ProCal tune. "If I wanted insane HP, I would have purchased a 2014 Shelby GT500!"