There are a few choices for me,like the followings:
Signal-to-Noise Ratio: The higher the ratio, the crisper the sound, especially when you want to crank the volume.
Built-in Four-way Power: While this is standard in most in-dash CD receivers, you'd better check just in case. Without this feature, you'll need a separate amp to crank your tunes.
Sound Control Options: You might only want simple bass or treble controls, or you might want a loudness control for a fuller sound, a bass boost to get you through your hip-hop phase, or a multiband equalizer and digital signal processing controls to fine-tune your sound to your vehicle's contours.
Security Features: There are many security options available--from detachable faceplates to programmable security codes and built-in alarms.
CD Changers: Having a multidisc CD changer will lead to safer driving and enhanced security. Load up several CDs before you drive, and you'll be ready for hours of listening pleasure and convenience.
Digital music CD Changer:A revolutionary product that allows you to connect your iPod or MP3 player directly to the CD changer port of your original car stereo for the best possible sound quality, it will even allow you to control it through the controls on your stereo and steering wheel.It is not an FM transmitter and does not transmit FM radio signals to your radio like other products on the market. Instead it connects directly to the CD changer port on your original car stereo to give you the best possible DIGITAL sound quality.
The last one is the latest one and I searched it on line and found there are three brank:Charmaker(http://www.car-cd-changer.net) , dension and Xcarlink on line.Have you heard of them?
Hope someone can give me suggesstion.Thanks
