This guide was taken from e9post.com forums, and was written by gIzzE
Here you will learn how to upgrade the whole system!
This really is a must do upgrade for any 'new' BMW owner of either the 1 series, 3 series, 5 series, 6 series, X3 or X5.
I had the L7 in the last car and this is better in every way.
This is only for cars with the stock radio or nav systems, it will not work with cars with the hi-fi option or Logic7.
Also it takes around 20-30 minutes to install and not one cable is cut, you can put it back to stock in 20 minutes. great for company car and lease car owners.
Here are some install pics to help you do it yourself if you want to.......
Remove Climate and Radio...
------------------
Remove connector and the optical cables if you have them...
Then plug your new cable into the existing cable and put the optical into the blaupunkt adapter....
Undo the trim under your glovebox (RHD) or steering wheel (LHD)....
And push the extension cable up to behind radio....
---------------------------
Connect the extension cable to the harness behind radio...
And start to remove trim to tuck cable down the side of the car...
---------------------------
Use a couple of cable ties to keep it under the trim and remove rest of trim to the back of the car to get to the trunk....
----------------------------
Push the cable through to the trunk where the existing wires go through....
And pull them through into the trunk...
------------------------------
Plug the cables into the amp and hook up positive and negative to battery..
I tucked the power cables under the boot floor..
Stand back and admire your work. Job done!!