Go with the Wilwood kit.....by the time you buy everything (including changing the BS silver color) for the CTS-V kit you're gonna be pretty close in cost but nowhere close in quality. At the end of the day...the CTS-V kit is a "passenger car" caliper and rotor.....and the Wilwood components are "race spec". Forged caliper with SS pistons.
You would have to compare "off the shelf" prices....not hodgepodge, hunt it down peice by peice....which is even more if you account for your time.
Paces CTS-V kit = $1400+pads+color change=$1950.
Wilwoods W6A kit = $1900 shipped from C5 vendor. You can get a better price cuz you live in Oxnard...which is only 1 hour from Camarillo where Wilwoods are born.