Actually the pricing is $1600. And take into account that Apple is already super overcharging on the current line of Mac Pros, if the 3.2GHz replaces the 2.93GHz model it will be pretty even with the prices now. Actually the prices would still be a little overpriced with the current prices as it is with the 3.2GHz silent upgrade for the top.
http://en.wikipedia.org/wiki/Nehalem_(microarchitecture)