Bose speakers and factory GPS in CLK

A friend of mine is about to take delivery of a 2000 CLK. My knowledge is not that geared towards new-fangled cars, where everything is electronic and little is user-serviceable. ;)
The car allegedly comes with BOSE speakers, but has a (broken) aftermarket GPS head unit. I would imagine the BOSE system is some kind of proprietary thing, with a hidden amp and maybe integration with a specific head unit? Am I way off target?
What's the easiest way to tell if this system is/was fitted?
Another question - how difficult is it to retro-fit the factory GPS unit if the car didn't come with it? Is the loom in place? Is there an external aerial? I saw a couple on ebay and I would imagine that breakers must have more.
Sorry for my lack of knowledge, and any links to the nitty-gritty of these cars are most welcome.
Antony
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.