The CTS-V was a surprise when it hit the automotive industry for the first time. The fact that GM managed to cram a Corvette engine with a manual transmission into a Cadillac was an eye-opening experience. The first generation of the car proved to be such a success that GM has improved the lineup with every generation (via Motor Trend).
The CTS-V in its most recent variation did away with the V8 engine option. But you can still find the older models of the car that came with the Corvette-derived power plant. It should be noted that the V8-powered CTS-V wagon is one of the rarest options. But the first-generation CTS-V models are also becoming harder to find in good shape.