Indeed it is [expensive] for what you get.
You can save 20% if you order it from Chicago BMW.
I got mine used from a friend who installed the antenna and the BMW CB Communicator. He didn't like the setup, and instead opted to go with GMRS radios instead. So, he sold it to me. I then resold the CB since it wasn't compatible with my model year, and I didn't want to mess with it's internal wiring to make it.
As for the antenna, you may have seen a previous post of mine
, mentioning that it wasn't long enough (according to my SWR measurements) and I was getting some squeal on transmit. So, at the advice of another clever forum member, I ended up getting a replacement antenna mast (meant for a Wilson 2000 antenna, and comes with the cap already on it) for $12 at a local truck stop that sells CB parts and does CB repair. Considering this (if you can get a mast locally), you might want to see what the individual parts cost (parts 2 through 9 on the diagram is all you'll need). Might save some money, as I'm sure BMW charges alot more than $12 for the mast (10) and cap (11).
By the way, I have the J&M handebar mount CB radio (JM-2003-SL
) wired into my Baehr intercom system. What kind of CB are you installing?