It now becomes apparent why Audi did not bump the facelifted R8 to 450 horsepower from 420. The reason for that was so that now with the successor they could say the new model is more powerful. They could have bumped it to 450 all along considering that is what they already had with the RS5 4.2 V8 which is basically exact same motor.
With the next generation RS4/RS5 set to ditch this old 4.2 V8 engine many hoped the R8 would as well for an exciting turbocharged powerplant. Unfortunately, that will not happen. The Audi 4.2 FSI V8 soldiers on.