Looks like they're quoting USD 169 for the DC ANR upgrade kit, which is about AUD 220.
It was a good deal back in the day, but I guess the ANR electronics are more common and cheaper now.
I want to get a pair of new ANR headsets for my plane, but it's a hard choice because there are so many good options.
One thing I did observe recently is that when you have an ANR and non-ANR head sets plugged into the same intercom, the background tone from the ANR (Lighspeed) is deafening on the non-ANR headset.