I choose Apexi Air Filter due to the reason that my research concluded that it is the best filtering air filter. Also, a lot of web site concluded that the most horse power gains produced by Apexi compared to others. However, not sure about this last point as I saw some other articles which put Apexi into 2nd or 3rd place. Overall, fantastic filter.
So, I purchased the largest Apexi Universal Filter 80mm for AUD$92 including p&h from Malaysia on EBAY. (Found the seller from a link in a forum, and asked him to relist the item) Filter look really good.
Now, my problem here was the adapter which get screwed into the air filter an goes into the intake pipe. It was around AUD$120 the adaptor alone, and some dealers sold both adapter and a smaller Apexi filter for more than AUD$200.
I also contacted some FTO owners from this club to see what they did with the adaptor problem. It seems to me that this is a general and expensive problem.
So I introduced my creativity and visit the Bunnings, here is what I come up with.

Instead of paying well over 100bucks, bought this metal (wont get rusted) for AUD$2.80, all you need to is to drill 4 holes.

With the help of the seal, I dont think any sealing problems will occur.
Overall, worked well. The new DIY adaptor is strong enough to not to be bent.
Hope this helps someone in this club as I learnt a lot from all of you guys. Very happy to put some input into the knowledge base as well.
Building the airbox now. So I will try to take some pictures and make DIY out of it too.
Please post your comments and/or possible problems might occur from this DIY job.