Just wanted to thank you for this writeup! I followed it last month and the rear parcel rattle I had in my 2011 e92 has been gone since. Only issue I had was removing the C-pillars, both sides would not budge no matter how hard I tugged and yanked...I decided to blow dry the whole thing to heat it up a bit (as I was working in a -15 deg C garage) and was able to yank it out after.
Now on to my less annoying rattles/squeaks...
2011 335Xi E92 Le Mans Blue 6AT M-sport with Exec and Nav package