The new Audis such as the Q7 and RS4 have already started their assault against the rival BMW and Mercedes factions in surprising fashion.
The Audi Q7 defeated the Mercedes GL450 as already noted on autospies.
The RS4 was tested against the C55 in Auto Motor Und Sport and it was the clear outright winner.
The RS4 was labelled as the sportier alaternative to the Mercedes CLK63 AMG also by Auto Motor Und Sport.
The R8 will surely be compared to the BMW M6 and Mercedes SL55 AMG. I'm betting that the R8 would win for better acceleration, handling and track performance when compared to the BMW M6 and Mercedes SL55. The M6 weighs MUCH more than the R8 and the SL55 was never designed to be a track star.
The Audi A8 has already won against the 7-series and S-class.
With the product assault, Audi is asserting itself as a major force and their sales just keep skyrocketing through the roof as a result.
The new TT has received great reviews.
I believe the R8 will be the true display of Audi's new rear-biased split Quattro and V8 engine at work.