Qisha didn't say it would be a 4.2N/A, only that it wouldn't be a Forced Induction version of that engine. I openly agree with that opinion, there is no financial case for developing a Bi-turbo of this engine when there is already a 4.0TFSi completing final testing waiting in the wings if the decision was taken for the RS5 to use such an engine.
I know I have maintained that it will be a 4.2N/A engine and stick by this statement but everything I believe in suggests to me that this decision would be the wrong one in the current economical climate unless Audi have miraculously made it more powerful, more economic and with much lower emissions. You are 100% correct in saying that v8 engine car sales have died a death at the moment but as all of these cars being discussed are either 10/12 months away or even 18/24 months as is the case for the RS4 is it correct in placing present day issues that might be well by on the mend by then.
Originally I was told that the RS5 would have been launch mid'09 with the RS4 appearing some 4~6 months later, the reality is that the economic slowdown has forced a delay in the launch of both cars and probably allow for a rethink of which is the best approach to market these cars, though they are still low volume products they still cost a lot in development and need to sell to at least break even if not make a small profit.
I welcome this delay as what ever decision is taken on engine choice will not be a rushed one just to get the product to the market, those days of 'if will build it they will come and buy it' are long gone and have been replaced with 'what will it take to make them buy it'.
It's a consumers market and only the best products will survive.