Understand what you're trying to achieve. I recommend using the correct components for your application. I've heard/read it can be done but never tried to adapt late model calipers myself but don't recommend it when there are OEM examples that will give you excellent brakes for little money.
That said, I'd personally go with a Brembo setup. And bonus, there are stock wheels that fit the setup without spacers. I'll find the part number for the wheels shortly.
If you choose to go this route; whatever you can send, or take back (like the rotors/brake pads), do it. Next, you need Calipers, 14" Rotors & Pads for a 2007 - 2009 GT500. Looks like you've found the correct 14" rotors but I'd double check to be sure before ordering (see attached). If you order from O'Reilly's (you're ordering replacement calipers/rotors/pads/dust shields; feel free to reuse bolts) just tell them you have a 2008 GT500. That should get you all the right parts. Not sure what the setup costs now. When I bought mine it was about $450 for calipers/rotors/pads and I ordered the dust shields separately.
For the correct part numbers and installation procedures see attached. Good luck.
19"x 9 Brembo Wheels - tires 255/40/19 or 255/45/19 (I use 255/45's). No spacer needed.
View attachment 83994