Get 3" ducts. Brake cooling is
very important on our cars, especially if you are full street weight plus a passenger, with the power levels you are putting down.
Like the others have mentioned, the kits you found will fit your car (the spindle is the same so the calipers will bolt up fine) but the wheel spoke/barrel clearance may be an issue depending on what wheels you have; most were made to be used with 18" wheels that weren't available in 2005, and the 15" GT500 kit needs very specific 18" wheels or 19" wheels for clearance.
Here are a few recommendations:
Wilwood:
http://www.wilwood.com/BrakeKits/BrakeKitsProdFront.aspx?itemno=140-13882-N&year=2007&make=Ford&model=Mustang&option=Shelby+GT500 There is also a 4-piston setup available for lower $$. The Wilwood "H" pads are pretty good for track use.
StopTech:
https://www.zeckhausen.com/catalog/product_info.php?cPath=11_90_1946_1948&products_id=3221 (We put these on 4 Mustangs here in AZ from 2008-2010 and they work very well, same as what came on Roush's "TrakPak" Mustang)
Also
@PAEracing can tell you more about the Brembo Pro Kit stuff here if you want something unflappable.
https://trackmustangsonline.com/index.php?topic=10577.0
Finally here is a long-running thread here on TMO regarding front brake upgrade options:
https://trackmustangsonline.com/index.php?topic=6570.0
However, for minimum expense,
I think you will be fine by rebuilding your front calipers (replacing the rears), and adding at a minimum 3" ducting plus the Ti shims. Vorshlag offers options to run 4" ducts, as well.
@modernbeat
None of those brake kits are going to work well without proper cooling.