I shouldn't think too much, if anything, will be officially released until after the RS5 later this year. (Audi of course won't want the potential massive coverage for both overshadowing each other.)
As per Darren's post above I've heard nothing at all through the grapevine. There were (a fair while back) rumous of a twincharged TSI V6 but that was probably just Fastlane making stuff up.
