Below is the link to the DSCA site, complete with the details of what the Goverment has requested:
http://www.dsca.osd.mil/PressReleases/36-b/2013/Australia_13-05.pdf
It goes into a lot of detail, 12 F/A-18E/F, 12 EA-18G, 54 engines, 35 radar systems, etc, etc.
All for approx $3.7Billion, but there is something missing out of the list and that is the jamming pods, etc, for the 12 new Growlers mentioned. Below is the link for the Growler Modification kits from May last year:
http://www.dsca.osd.mil/PressReleases/36-b/2012/Australia_12-27.pdf
Total cost for the kits was $1.7Billion, brings both projects to a total of about $5.4Billion.
I would assume that if the purchase does go ahead, the total cost would actually decrease due to not having to pull the 12 'pre-wired' F's from service and modify them to Growlers.
Yes some money will have been wasted on the 'pre-wired' airframes, but that will probably be offset with obtaining 12 new builds, and I suppose it also means that if in the future we needed to have more Growlers or need attrition replacements, then the 'pre-wired' airframes could be used.
It's also interesting that, apart from the 12G's mentioned, the request mentions 'E/F', does this indicate a 'mix' of E's and F's?
As Milne Bay said he was expecting 24 single seaters, I was assuming a mix of maybe, 18 E's, to replace one of the Classic Sqn's, and probably 6F's, to be used as trainers for 1sqn, the Growler Sqn and the replaced Classic Sqn.
Or maybe it will be 12 F's, otherwise we will end up with more types and 'sub' types, eg, E's, F's, G's and eventually F35A's too.
But if this does go ahead (I'd still like to see the full F35A purchase go ahead, but it appears that may not be the case), it probably makes sense to buy new Growlers and not have to worry about pulling the 12 airframes from service that were going to be converted.
From memory, the plan announced last year, for the conversion of the first 6 Growlers wasn't due for a number of years yet and the conversion of the final 6 wasn't going to happen till the first F35A Sqn came into service, eg the early 2020's.
Be interesting to see what the 'plan' is when eventually announced!