Absolutely no need to unzip the rear window. Very ingenius, very easy, very quick to open and close. (The rear window can be replaced when cracked by unzipping with specials tools)
An accoustic alarm will sound if the trunk is still open! This will prevent the two lids to collide with each other.
There is also an optional hardtop available from Fiat or
Wiesmann.
Also check out the windstop!