[illumin8]

This really wouldn't work for any car made in the last 20 years. Most of them have anti-theft systems that require you to put in a PIN to use your stereo if it ever gets disconnected from the battery. I suppose you could type that in every single time, but there are other computers like your automatic transmission management that learn how you drive, etc, and might not like to get reset every day.

[windowsrookie]

This is false. I have owned many different cars from the last 20 years and none of them did this when you disconnected the battery. A quick google search shows that it's Hondas that do this, not "any car made in the last 20 years".