There ain't NOTHING "regular" about the powerplant and tranny in the CTS-V...
I will freely admit that the plain-jane CTS makes me queasy and close to hurling as the looks are extraordinarily questionable on it, but GM dressed the CTS-V up nicely and it shows that.
I really find it not much different than what Ford did for the Contour as compared with the Contour SVT in terms of "dressing up" for that fact. I never looked at the Contour as a mode of transportation; that is until the SVT came out. I just never found the non-SVT Contours that "inspiring" of a view. IMHO, of course.
Then comes the aftermarket discussion...
I've talked to one of the reps at Lingenfelter and from the discussions I've had, their current S/C application for the LS6 is close to a bolt-on as it is (only a few packaging issues to take care of).
Headers, a better exhaust, S/C kit (intercooled) and a beefed-up clutch for, say something around $9-12K and you are looking at a luxury sports sedan putting something in the neighborhood of 550-600 HP down (depending on the extras)...
All backed up by a 3-year warranty from the aftermarket provider, I might add and it's STILL cheaper than any other comparable 4-door sedan on the market.