The ZX800/GT3 replaced the ZX700 at the factory within the last year. The new unit has had many internal updates, but it also incorporates an HD video connection for use with an HDMI cable and Bluetooth streaming audio and hands free cellular operations. The Bluetooth has been a huge success as people have really loved it.
You can use any 110V TV to upgrade to if you go with a ZX800, but if you go with a XZ700, you will need to ensure your new TV has a single yellow composite video INPUT. The ZX800 will work with the TV's HDMI connector. You can also use digital audio outputs from your TV to the ZX700/800 which will give you 5.1 surround sound when the TV show you are watching is encoded that way.
You can also get a wiring harness adapter (Concertone® ZX690 Adapter
) to make the upgrade a plug & play replacement.
Please feel free to contact me directly for more information or advice on what to get.