To understand that the current Z4 is radical even too much for some .
The next generation Z4 Roadster progresses the radical angle further but is also groundbreaking. Z4 Roadster will be the first performance Roadster , a BMW performance Roadster featuring "Efficient Dynamics"
To help in it's quest for greater efficiency . Construction of the new Roadster is geared towards using lighter materials from areas such as the full aluminium front end , magnesium crankcases and engine blocks and aluminium body panels. Even the folding hardtop offers a lighter steel than used in the E93 3er Cabrio.

Where the BMW Z4 Roadster will be groundbreaking is the introduction of the first BMW diesel powered Roadster. With it's adoption of BMW's highly powerful 204PS diesel engine currently winning acclaim in the BMW 1er Coupe. Using a standard powered soft-top roof to keep weight down to the bare minimum with the lightweight materials already utilised and "Efficient Dynamics" technology to deliver eco friendly driving pleasure , with substantial performance and greater efficiency.

BMW hope to see the Z4 offer best in class performance, dynamics , agility and efficiency. Even moreso the Porsche Boxster remains the benchmark here but the engineers have had their fair share of drives in the Lotus Elise models to deliver a similar type of agility and offer an individual outlook to the segment with the dynamic handling of the new Z4.Roadster.

When the Z4 appears by December you will see it's followed the 3er Coupe and Cabrio and moved up one notch. Although you did eventually see the reason why.
The BMW 1er Coupe and Cabrio.

Which is why you will see the segment below the Z4 become very creative indeed , think of the original Z3 and you can see how many with BMW miss that car's compact proportions and how the new Z4 Roadster opens the door and leaves space for the upoming BMW Z2 Roadster.