The xd is a perfect fit for the stock location.(minus the amp rack)
From the systems I have seen right here in the audio upgrade section.
The ms-8 can go next to the TCU and the amps usually go in the
the stock location. Some people add the cd player storage kit then they can get a couple of pieces in that location.
There are multiple examples of an ms-8 plus amps in all the system examples
in the stereo http://www.e90post.com/forums/showthread.php?t=641323
I haven't bridged on the XD but you can download there manual from the site . I kind of remember you might need Y Rca adaptors
for the Inputs to make the bridged configuration work.