Wow so much misinformation and fanboy-ism here
For those of you who don't know, the RS5 has already been out in Europe for a few years. Those of you saying that Audi has had so many years to catch up to the BMW M3, well you're just making asses out of yourselves because they've both been selling side-by-side for some time in European markets.
Now to those who say the 4.2 V8 in the RS5 is the same one or similar to the 4.2 in the RS4, you're also wrong. The 4.2 in the RS5 is derived from the 5.2 V10 in the R8, and has little or no relation to the previous 4.2 V8 in the RS4.
I'm not even an Audi fan but I know this stuff. Kids, do your homework before posting.
Having said all that, I would trade my higher-power CTS-V in for an RS5 simply based on looks, motor, transmission, and AWD.