How easy is it... Get to the back of factory car radio...?

It's not difficult. I had to help my neighbor with this last year... if I remember correctly, the first thing you have to do is pop off the ring around the ignition. You can do this using a flat screwdriver (cover it with cloth if you dont want to scratch your interior). The console also has a trim that can be popped off using a flat tip screwdriver.

Once you have the trim pulled off, unplug the display from the top. Around each set of components in the console are phillips head screws. You will have to remove each component starting from the bottom and working your way up to the radio up top. Once you have done this job once, you will find it extremely easy to do it again should the day come.

You may need to move the shifter out of the way (put in neutral) to get the sections out.

I found the best thing since sliced bread...http://www.crutchfield.com/S-9oDEWuNVIo6/cgi-bin/p...

It's not wireless so there's no interference. Not to be confused with an FM transmitter. Basically it adds an AUX input to ANY radio. No searching for a clean channel.

It feeds your audio signal from a headphone jack ( or RCA cables) by FM modulation, directly into the antenna input on your radio bypassing the antenna when on, allowing the radio to work as normal when off. It comes with an On/Off switch.

This is the answer. Totally versatile.

Here's one in action - http://www.youtube.com/watch?v=MHBI0LBGhR0