I confirmed with Matt that it is infact the Air Fuel sensors before the Cat that needed replacing.
After searching and researching the internet trying to find part numbers on various websites, i have had a great success i think.
Subaru genuine parts was no good as none of the part numbers appeared to line up with the ADM numbers.
Denso had product numbers but no Subaru part numbers so i found it hard to cross check.
I found the part number on this site
http://opposedforces.com/parts/legacy/en_b13/type_83/I went to my local Subaru parts girls to verify the part number 22641AA160 against my VIN and it was confirmed as the AF sensor. They also let me know Subaru charge a whopping $460ea
Now the search was on to find a cheaper price which didnt take long at all. Plug the part number into google and there was many options. Oddly enough the UK was the cheapest by far. But the best thing was i found a seller on ebay from the UK. So risk free shopping
http://www.ebay.com.au/itm/181095335009?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649All up $320 for both sensors delivered to my door