I tried to do the ducting on the first one I made, but I just didn't have the proper tools available to get a nice clean cut so I ended up scrapping it. When I make the stage II intake, it will have the full ducting available. In the mean time if I can get a hold of a dremel I will set this one up too.
As for the filter, I have been running K&N's for a long time and never had an issue. The first thing I do when I get one is use the cleaning kit to remove all the oil, then re-oil it my self with the proper amount so its not dripping wet like it is when you first get it.
Never had an issue ever, no codes no nothing.