You can get a HKS AFM adapter for the MK3 Turbo for ~$35. You can get a regular cone K&N for $35-40. Some of the adapters/filter combos I've seen on e-bay are even cheaper than that as a package.
Not sure what if any difference there is between the adapters.
I sell the K&N and HKS-Adaptor pkg on my site. If you want to play with the ebay folks, you have that option as well. I am outselling the FIPK 5 to 1 with this low-buck setup.