2750 North Main Street
Mansfield, TX 76063
They are a dealer for J&M, they should be able to hook you up at a reasonable (non-bmw) mark-up. In example A&S wants $97 for a lower headset cord made by J&M. J&M sells the same cord for $25!!!! Just burns my butt!
Or call j&M directy! http://www.jmcorp.com/
As for the FRS/CB/2 way/Ham Radio issue. Good luck. I have made cords to connect Icoms to the Voice II. Baring the factory option (no longer made) kenwood, its a crap shoot as to compatability. CB, there is always J&M, Ham (not experienced) but there is one ham radio that I can't remember people tend to use, but then you still have the cord issue to deal with.
XM Radio Capability: there is a mod, $40 (use the search function), that connects a BMW car (5 series) aux jack to the back of the stock radio. it will do the same thing as the aux jack on the comm system, but allows for the speed volume to work and use of the volume on the bars, were as the comm aux does not.
GPS- I'm a cheap bastard and get used garmins from craigs list, I don't pay more than $60 and mount it and go, yes over time (second one in use over two years) it will fail due to weather, vibrations who knows. but it beats the heck out of paying over $600 for a "bike" approved one, and if it gets stolen or drops, big deal!