I'm not sure on that. I just remember reading somewhere that the GT had different shocks than the 2.5i and 3.6r. Best bet would be to check with the dealer parts department.
I went with the 19mm RSB because its only $80 and I don't need to change the endlinks. Also it looks stock, nobody will ever notice it has been changed.
Speaking of Koni. Someone who is local to them should think about maybe doing this...
http://www.koni-na.com/testfits.cfm
They may decide to release some stuff for our cars.