Are you the switched-on environmental type who plans your Prius journey around how much air resistance you're likely to encounter on the way to Whole Foods? Rejoice! Now you can stop worrying and learn to love your car stereo if you purchase Pioneer's newest Navigation Unit designed specifically for electric vehicles, the AVIC-ZHO9-MEV. Hiding behind that easy to remember (and decidedly catchy) name is a device that estimates your car's r