Not on an Interstate, but I have the Zumo 660 integrated to the J&M CB2003. If you are comfortable removing the fuel tank, running various wires and cables, and stowing things in nooks and crannies, it's an easy install. The installation instructions are straightforward and everything went smoothly. My Zumo had no problem recognizing the 16GB SD Card, and the Bluetooth phone capability is really convenient. You might also check out
http://www.zumoforums.com/index.php?PHPSESSID=349f4820002d99b4a1f7b8e926200184&.
Make sure all the connections are fully seated before putting everything back together and make double sure you don't kink the tank vent line. Don't ask me how I know about either of those pointers...
