Thanks for the DIY! I completed the TCU retrofit with BMW Assist with little trouble (and I'm definitely a novice). Thanks out to Evan of Tischer for a good deal on all of the parts too.
If you have a sedan and don't have drop-down back seats, use this thread to take the back seats out:
http://www.e90post.com/forums/showthread.php?t=4646.
I like this thread for the FCZ removal (without a screw driver):
http://www.e90post.com/forums/showthread.php?t=97545.
And I like this one for disconnecting/reconnecting the MOST bus wires:
http://www.e90post.com/forums/showthread.php?t=376617.
Thanks again, AoshichanX! Great stuff. Next up, a factory Sirius retrofit....