First of all I'd like to say this forum is very helpful. I have a 2006 e61 produced 07/05 and am having issues with water in the trunk. It's coming in down the the ketand right rear pillars after a hard rain. I've been researching the drainage and am at a loss. I took the rear passenger wheel off and the drainage plug "+" can't be found. Before i take the bumper off is there a different location? Thank you.

 

The manual crank works with less resistance if you unplug the electrical connector from the front sunroof motor.
If you drop the rear portion of your headliner you can approximate where the same manual crank feature exists for the sunshade "floating headliner" motor. Drill a hole in your headliner and operate the manual crank (if you're desperate to get the sunshades open).
I installed 3 of the panoramic kits (front glass, rear glass & floating headliner). It was at least a 12 hour job, partially driven by the hours spent studying the repair instructions and SIB's on the topic. The second time around would probably take half the time. Like other's suggested above, I'd just focus on getting the rear drain tubes cleaned...