[MotorsportsAuthority aka Dragon]

Cost of Materials are higher and the more expensive brands actually do R&D to optimize their filters, whereas the cheaper ones are the same filter made in whatever design. Some of the cheaper ones are sponges. Most upper brand filters are rechargeable, and therefore have multiple uses, whereas the cheaper ones...once they're dirty, it's time to replace. There's no telling to say that the cheaper ones are going to perform better or worse than the upper systems, since the cheaper ones are tested.