Why not just get whatever car you want?
The whole GT/CS vs Brembo crap has been going around forever. If you don't track your car, the Brembo or Track package is a waste...especially if you're doing aftermarket work to your suspension down the road. Likewise, you can turn any Mustang into a GT/CS (looking, at least) if you buy the right aftermarket parts.
Honestly, just get what you want. You can always modify it later to make it exactly what you want. Minus the glass roof of course...you should really get that from the factory because it's awesome.
2013 Mustang GT - 402A GT/CS - 6R80 - Glass Roof - Engine Block Heater - SGM Exterior - CB/Miko Interior
Steeda Adjustable PHB (Street) and Steeda PH Brace, Stainless Works Retro Catback Exhaust...