I have the Phoenix Automotive 12.1" touchscreen in my 2012, and it takes about 30 seconds to boot, it can be a little laggy at first, and I'm still figuring out all of the media modes, but it looks killer... The tach on the display works great, but the speedo is off by about 40mph, lol.
12.1" Vertical Screen Android Navigation Radio Car GPS Navi Multimedia for Ford Mustang 2010-2014
Can you post some pictures of it?