Put a K&N filter on my Tuono V4 tonight. I did notice that the filter was shaped a bit different than the standard one. Yes, you leave off the standard hold down cage, but what I failed to notice is that there's a second part (the bottom half) of the cage that has to be removed also. Once I removed the front two screws to screw the new filter in place is when I figured it out. I wondered why the screw holes weren't in the same position of the standard filters. Oh, and I wondered why the air box lid didn't fit right either! Felt rather dumb... Who else will admit that"¦..?