On a 2007 Pony Package V6 and on the GT model? Going to go order slotted/drilled rotors from brake designs but apparently they give two different options for rotors. I thought the caliper was the same size?

 

The myth is that the calipers are the same...

 

The GT uses the same caliper but a different caliper mounting bracket and larger rotor.

 

So, I wouldnt be able to have the GT rotors fit properly, if ordered?

 

Not unless you got the right and left GT caliper brackets.
They are about $34 each from the dealer. I have the part
#s somewhere if you need them.
Also GT front rotors wont fit on 16" stock wheels with 39mm of offset.
You need the 17" 45mm offset or larger rims to accomidate the
larger rotors and moved calipers.