you can take the airbox off the bike completly and use 2 round style K&N filters with outers to attach to the end of you stock boots. Much earier to remove the filters for cleaning this way. Direct mount filters can be used with the FCR carbs because you can purchase spigots for the back of the FCRs that are like velocity stacks so they help channelize the air charge into the carbs, the stock boots do an excellent job of channelizing the incoming air charge as well. I've done a bunch of dyno testing to find what works and all my bikes use the stock boots into the back of the carbs with duals K&Ns on the backs of the stock boots and no airbox. The cost of the 2 K&Ns and outerwears to go with them is about 150 bones.