AUSTRALIAN BMW Z4 designer Calvin Luk has revealed that the just-launched third-generation sportscar will be available only as a soft-top roadster, ruling out a hard-top version that was a feature of its predecessor.

In an interview with GoAuto in Melbourne this week, Mr Luk said that from day one the new Z4 was a soft-top-only affair.

“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,” he said.

Mr Luk added that the decision to go for a soft roof over a retractable hard-top was mainly at the behest of BMW’s engineering division, and that it was not up to the design team to decide.

“More coming from engineering,” he said. “I think mostly engineering, there may have been some market feedback influence on that, but I would expect it to be engineering – performance-related.”

The soft-top was introduced to save weight for the new-generation roadster, which also uses metal panels between the layers of fabric to ensure the car keeps a sleek profile with the roof up.

Mr Luk said that when designing the Z4 – his fourth model design for BMW after the 1 Series facelift, X1 and X3/X4 – he was allowed room for creativity due to the Z4 being an extroverted and niche product for the German prestige brand.

He said the design briefs for the car were quite vague, allowing him to create a ground-up design that differentiated itself from the rest of the BMW range.

Mr Luk took inspiration from the quirky Z8 roadster produced from 2000 to 2003, which is evident in the headlight design that features stacked semi-hexagonal LED headlights rather than a horizontal design as seen on all other models.

Another feature is the mesh-style twin kidney grille which replaces the traditional horizontal slats – and which took around 18 months of development and some convincing of company executives before the green light was finally given.

Having launched in Australia last month, the three-variant Z4 range is topped by the hi-po M40i, which is powered by the same 250kW/500Nm 3.0-litre turbo-petrol inline six-cylinder engine as the A90 Toyota Supra coupe.

BMW M GmbH chairman of the board of management Markus Flasch told Australian journalists, including GoAuto, last month that there were no plans to introduce a full-fat Z4 M, and Mr Luk told us this week that he had not drawn any sketches of what a properly M-fettled Z4 may look like, pouring another dose of cold water on speculation that a Z4 M could be introduced at a later date.

The new Z4 range opens at $84,900 plus on-roads for the 20i, up to $104,900 for the mid-spec 30i and $124,900 for the M40i, which represents a $30,000 premium over the top-spec Supra.

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