I didn't see the crank holding tool to rent. It looks like this. You can find them online for $60-$80. There are a few different brands.
I am willing to lend my crank holding tool if you pay shipping and send a deposit; the deposit I will return when the tool comes back. PM me if you want to do that.
Yeah, the aluminum reinforcement plate is crazy. I'm a little curious about your bolts. Mine all use 16mm sockets/wrenches. The stock BMW bolts are said to be 1-time use (It has a torque-angle spec - the book says 41 ft-lbs plus 90 degrees) and the price has drifted up from $4 each to $13 each. There is a whole thread on this -
http://www.xoutpost.com/bmw-sav-foru...olts-nuts.html