The engineers made the decision not to use a folding hardtop.
"From the beginning, we knew that it was going to be a soft-top mostly just because of the performance advantage in terms of the weight, so we didn’t need to mock up an alternative to that," Luk told Australia's GoAuto.
He also said that giving the new Z4 a folding soft top was a decision from the roadster's engineering team, not the designers. According to Luk, there are still metal panels hidden beneath the fabric as a way to make the car look better when the top is up.
To make his job even harder, BMW executives didn't like Luk's plan to use a mesh interior for the Z4's kidney grilles. It took the top brass about 18 months to grant permission for the design, rather than the usual slats, Luk told GoAuto.
Rendering artists have already imagined how the new Z4 would look as a coupe (see above). The result is a vehicle that looks a whole lot like the new Toyota Supra, which shares the same platform. The close similarities might be part of the reasoning behind BMW's decision not to develop the hardtop variant because the resulting model might step on its partner's toes.
The Z4 is available as the range-topping M40i with 382 horsepower (285 kilowatts) and 369 pound-feet (500 Newton-meters) in the United States, but the mill makes 335 hp (250 kW) and 369 lb-ft (500 Nm) in Europe due to more stringent emissions regulations. The Z4 sDrive30i with a 2.0-liter turbocharged four-cylinder makes 255 hp (190 kW) and 295 lb-ft (400 Nm). Europe also gets the base Z4 sDrive20i where the 2.0-liter turbo makes 194 hp (145 kW) and 320 Nm (236 lb-ft).