The type of filter really depends on what you intend to use your machine for.

If you're just bashing on asphalt or zipping around in parking lots, I'd use the least restrictive filter available, which are the foam filters that have absolutely nothing inside restricting air flow to the carburetor.

Check eBay item number 320085903120 to see what I'm referring to.

That filter in particular allows so much air flow into the carburetor that it instantly leans your mixture to the point that minimal adjustments are needed to fine tune your machine from the factory presettings, assuming that you have in fact removed the carburetor restrictor. What you get is a engine that's consuming a healthy amount of a fuel at a healthy lean setting. Basically, great performance without starving the engine for fuel.

If you're racing, bashing in dirt or other areas where you'll come in contact with a lot of debris, you're best bet is using a foam filter with some sort of paper element on the inside to prevent anything from getting into your carburetor / crankcase. Far more restrictive and you'll spend some time tuning, but it isn't hard and at least your motor will be perfectly safe.

The AE factory Team kits come with that type of filter, which is part number 7705.