What replaces the roof is a fully automatic,
multi-layer folding roof with a big glass window, and likely to be the biggest fabric roof in serial production, that will sit invisibly beneath the extended boot deck when it's down, but should give all the benefits of the coupe when up.
Stripping the car back to basics and returning to the roots of its original forebear, the Z3, also means ditching the old Z4's heavy, complex
folding metal
roof in favour of a
multi-layer cloth
roof and two large buttresses behind the head restraints.