With Typhoon, Rafale, F-15E(customized for your country), and F/A-18E/F all having been the subject of several competitions recently, I would think that all of the cost (both purchase & long-term), performance, offset, etc. info that anyone needs to compare them is already available from governments friendly to Australia... therefore there is no need to do it all over again just to get the same data.
The pro-F-22 mob (including Carlo Kopp) are already countering with claims that the US Deputy Defence Secretary: A) does not know what he is talking about; B) does not have the authority to make that decision; C) never sent that letter at all... it is a lie by Defence Minister Brendan Nelson to cover his arse.
This of course ignores the following: A) England is in a post where he would be part of the process of making such a decision; B) would not be making that decision, but would surely know if the President, etc had made that decision; C) would not make any such claim unless his bosses would back it up, due to the political ramifications of saying it if it weren't true; D) Nelson would be exposing himself dreadfully if he were to make up something like this... it would be easy for the Opposition to verify or disprove, just by talking with the Democrats in the US... now that they control Congress, they have to be fully informed of all such things, and have no reason to protect any deception by a representative of the Bush Administration... therefore it is extremely unlikely he would say such a thing if it were not true.