Top Gun has it right - emissions is the reason they don't come with this tune. There are people out there gaining 60HP, 75 ft lbs torque, and increasing gas mileage by 15% in the process... it's a win/win

You can read accounts of BMW drivers who were there testing the M5s, and took a CTS-V around the track, and admitted it was a superior car. There's no doubt it outperforms (read: acceleration, slalom, braking, handling) the Mercedes E63 AMG, the BMW M5, and the rest of the 4 door audis, chargers, etc. However, there is one car that's given the V a run for its money - that's the Porsche Panamera. The only 4 door car to beat the Nurburgring time the CTS-V set. However it can also be argued that Porsche spent several days setting their record, whereas the world record the CTS-V set was done on its first attempt - and the Panamera beat the V only by 2 or 3 seconds. Still, the Panamera, while with a $40,000 price tag difference to the CTS-v, is still a great car.
Yeah went with an automatic, because with this much power, there's not even a reason to have a manual gearbox

still, it's got a pretty impressive 'manual' mode