Here are the other V part numbers(and prices), if you want to mod it all the way:
All body pieces come with a primer coating(need to be painted). These are the parts straight from GM (no aftermarkets) at the lowest price possible:
Front Facia: 12335777
GM LIST: $521.61
GPD PRICE: $307.75
(This is the main bumper cover, 1 piece)
Front Facia Extension (L&R): 25750634 and 25750635
GM LIST: $28.85
GPD PRICE: $17.02
(The front inside fender well since the front facia is longer)
Fog Lamps (L&R): 25753700 and 25753699
GM LIST: $232.07
GPD PRICE: $139.24
(these are different part numbers from the regular CTS - don't know if regular CTS ones can be retrofitted)
Front Bumper bar: 25764982
GM LIST: $162.12
GPD PRICE: $95.65
(This is behind the facia, like the fiberglass bumper)
Grille, upper: 21996486
GM LIST: $292.61
GPD PRICE: $172.64
(Wire Mesh Grill)
Grille, lower: 25750638
(wire mesh grill; must install front fascia/bumper cover to fit)
Front door Side Skirts(L&R): 88980499 and 88980500
GM LIST: $120.76
GPD PRICE: $71.25
Rear door side skirts: 88980501 and 88980502
GM LIST: $105.40
GPD PRICE: $62.16
Rear Bezel/Neon brake light strip (part numbers by color/no need to paint)
iamond White: 25763604 Black: 25763598 Silver: 25763601
GM LIST: $506.02
GPD PRICE: $303.61