I bought my '05 V-series CTS in April of 2010. I traded in my '08 Saturn Sky Redline because it was just too small and impractical. Ironically, the color of my V is called "Redline".
The only current performance modification is a Magnaflow catback system.
Recently I had to replace the stock motor mounts with urethane ones from Creative Steel. I also have a BMR pinion support brace which I needed after I broke one of the mounting tabs off the rear diff with a hard shift.
Appearance mods include custom clear front turn/fog light lenses, HID 6000k fog lights, clear front side markers, and 20% tints on the sides and rear.
The interior is basically stock with the exception of the modified radio stack. I removed the OEM 6 disc in-dash CD changed and relocated the climate controls lower down to fit a 7" pioneer touch screen head unit. The Pioneer unit is wired into the stock radio and plays throught the stock Bose amplifier and speakers. Volume and audio settings are all still controlled by the stock radio. In the trunk, I added a 12 JLW7 sub running for a 800w JL mono amplifier.
In the next month or 2, I will be installing a Powerdyne Scorpion XB1A supercharger. The install will be completely custom and should be done by spring 2012. A cam swap may also happen then too.
UPDATE: As of February 13, 2011, the car now has a C6 ZO6 LS7 clutch setup, including LS7 flywheel and slave cylinder. The stock CTS-V dual mass flywheel failed several months ago and collapsed on one side causing improper clutch disengagement and a vibration. Now that the car is fixed, plans can move ahead with the blower install...