PhatNoise licensed its technology to Kenwood, then turned its expertise to supplying equipment to automakers and owners of cars with integrated audio systems that can't readily be swapped out. The interface needs tweaking; sometimes, instead of a song title, you see a CD number. But for music lovers who want to control what they hear, the PhatNoise PhatBox is the best choice.

The PhatBox provides adapters that trick your car into thinking it has a factory CD changer riding in back. Track and title info either show up on the factory radio display or are announced by a synthesized voice; you use the radio buttons to change modes and pick songs. The PhatBox has a USB 2.0 PC docking cradle for fast transfers to its 20GB hard drive. PhatNoise offers 40GB and 60GB systems for an extra $99 and $199, respectively, and the hard drive cartridges are compatible with the Kenwood Music Keg systems.