I ran across this PDF FR flyer this morning that covers both the 2012 and 2013 cars.
The Boss lowering springs must be getting close to being released as there's a part number: M-5300–BR
Note there's also a High Performance Clutch Line upgrade advertised in this flyer, hmmm: M-7512-A
Also a 2013 302S grille is going to be offered too.
http://www.fordracingparts.com/images/part/high/Ad%20Slick%20PDF%20Folder/mustangpartssheet.pdf
The Boss lowering springs must be getting close to being released as there's a part number: M-5300–BR
Note there's also a High Performance Clutch Line upgrade advertised in this flyer, hmmm: M-7512-A
Also a 2013 302S grille is going to be offered too.
http://www.fordracingparts.com/images/part/high/Ad%20Slick%20PDF%20Folder/mustangpartssheet.pdf