Im presuming the tail is of the pop-up variety which lifts at around 75mph+, or more likely just an OTT add-on to disguise the true shape... its roumered to start at £55,000 ($110,000) in Europe, but you'll end up paying less Im sure.
I'm looking forward to the NEW 928s, now Porsche and Audi are in talks to co-develop there cars (as I'm sure you know, Porsche owns around 33% of the VW Audi group) a new 928 looks even more likely. Apparently its to be based on a modified next generation Cayenne/Touareg/Q7 platform !