Same here! It's so easy to get the tail loose on my car (when I want to), I'm assuming/hoping it has Posi, but it really got me curious the last time I did it.
'13 F10 BMW 535i Sport
: Jet Black/Black-Anthracite : Premium & Technology Packages/Sport Auto Trans/Camera/Park Distance Control/Heated Seats/Tinted Windows/Blacked Out Markers/Performance Spoiler.
Ex M-B's: '11/'10/'06 E350's w/ AMG Sport Package, '02 S500 w/ Every Option.