I fully agree with the previous poster, but I think maybe a little higher for the base model. You might see an initial low $60's base model but it will not be a buyable car (everyone will have at least some options, plus dont forget the likely gas guzzler tax in the $2k range).
Realistically, a middle of the road configuration - low $70's.
Fully loaded may reach $80k.
The current e46 M3 can reach $72k already.
And look at the competition, the RS4 is into the mid $70's and people are lining up to buy it.