Thanks for letting me pick your brain on this issue. I have been researching the heck out of this and it seems that your way is the most logical way to install this unit.
I have just taken apart the side panels in the trunk in an attempt to identify my amplifier but to my shock, NO AMP! Could it be that my radio is powering all the speakers on its own? Would BMW have placed the amp elsewhere? I am stumped......I just wanted to see if the amp was a logic 7 or not so I can determine whether or not the install would be possible.