Cold Air Intake Like mufflers, OEM air boxes have become quite good, so the gains from an aftermarket cold air kit might not be night and day. However, they do offer a unique look and one less restriction in the intake tract that may prove problematic as your build progresses. Many also offer a washable and reusuable filter that comes with a warranty. VaraRam, Airaid, K&N, Spectre Performance, and Cold Air Inductions (CAI) are just a few options on the market.