The Audi ways a ton and handles it's weight too from the reviews I've read. Aside from that these things have absolutely wretched reliability. Something you won't have to think about with the CTS-V, which I'm sure also includes the 100k GM powertrain warranty.
I've come to the conclusion that German cars, while very attractive in a variety of aspects, really offer nothing more than temporal automotive fashion. Whether it be technology, design; these things are NOT designed to last, they're designed to break so that when they do..... you go get a new one. I know you can say that for cars in general, but I think this sentiment fits the German car to a "T".