The Problem
Most factory installed mobile audio systems leave the owner with few expansion choices. Adding a hands-free cell phone adapter or an upgraded tuner for HD Radio or Satellite Radio seems virtually impossible, and risky. Factory installed systems are complex, they’re integrated with the car’s computer systems and removing and replacing components can void the vehicle’s warranty. Modifying a leased vehicle has even greater risks.
Aftermarket Solutions
Aftermarket manufacturers have developed several smart solutions that solve the dilemma. Several companies now offer products that enable vehicle owners to expand their mobile audio systems without modifying the factory system or tearing apart the dashboard. Adding a navigation system, a digital music player, upgraded tuners, multi-disc changers, hands-free cell phone systems and many others is easier than ever. The expansions systems are known as external media controllers, essentially a ‘black box’ that is installed under the dash or under the seat that allows connection of several components.
Kenwood offers a line of three ‘Car Portal’ expansion products, which permits adding multiple audio/video components to an existing mobile audio system. For example, the Kenwood KOS-V500 
has built-in amplifiers with 50 watts x 4, a USB input, two sets of A/V inputs and outputs, and three pair of pre-out connectors for external amplifiers.
Alpine’s VPE-S431 Video Switcher/Expansion Module features one A/V output, three A/V inputs and has multi-zone control for separate front and rear seat entertainment options.
One of the best features of the expansion products is they can be taken out of the vehicle when it’s sold or turned in when the lease expires, allowing the owner to install them in another vehicle.
