I am in the process of big brake project with 14" rotor w/ Wilwood 6 piston calipers up front and 13" rotor with Wilwood 4 piston calipers at the rear. Rear has been done already and the fronts have been on hold due to 380 project.
With big brakes, of course, our factory spare tire solution does not work. Also, with spare tire being 20 years old, not so sure I could trust the spare. I had been periodically checking the Ebay for CTS-V spare. However, they were quite pricey and I had been holding off. Then, all of a sudden, ex-ZR-1 owner who currently drives a CTS-V sends me a message through the Net Registry and offers an extra brand new CTS-V spare he has for a killer price. I just couldn't resist. I will have to have the center hole bored out to work with ZR-1 hub but, in my opinion, the best spare tire solution there is for those of us who modified to big brakes.
Of course, QB93Z (Jim) reminded me the other day that should I have a rear tire blow out and if I have a passenger with me, there may be no place to carry the rear tire since I have a subwoofer in the hatch... Ah, well... At least 50% chance it may be one of the fronts.