i use the pureolater pure one, its a solid blue filter with a silver label on it, comes in a silver box, model 4610 or 4612, one is like a 1/2" longer than the other both work, and i have heard, and read they are the best overall filter etc., fuck that stupid nut on the K&N anyways. I get mine at autozone and buy everyone they have when i go to the store, have 2 sitting in the garage.