The move also means it is a key differentiator with the upcoming, hard-top Toyota Supra with which the Z4 has been jointly developed.
Improved driving dynamics was the focus of the new Z4, said Ederer, helped by an extremely rigid body structure and chassis mountings, new front and rear axle design and variable sports steering.
An M Sport differential and Adaptive M suspension comes as standard on the M40i and are optional on the 20i and 30i. Ederer said: “The sport differential allows you to steer with the rear rather than on the throttle. It’s one of the most exciting things it can do. We always wanted to keep it rear wheel drive.”
Three trims will be offered in the UK: Sport, M Sport and M Performance, although the latter will only be available on the M40i.
Pricing is expected to start from £36,000 rising to £48,500 for the range-topping M40i when the Z4 goes on sale in early 2019.
The brand revealed its new, third-generation Z4 last month, with a renewed focus on driving dynamics to take on the Porsche 718 Boxster.
The new roadster, which has been developed in conjunction with Toyota’s upcoming Supra, made its public debut in the US at the Pebble Beach Concours d’Elegance in Monterey, California, with global sales due to commence later this year.
The Z4 will makes its European debut at the Paris show in September, when BMW intends to reveal more about its mechanical package ahead of right-hand-drive deliveries to the UK in early 2019. The initially revealed model is the flagship M40i M Performance First Edition, which uses a 335bhp turbocharged 3.0-litre straight six petrol engine.
The 718 Boxster rival has been designed and engineered from the ground up in a move aimed at reigniting buyer interest in roadsters in the face of dwindling sales over recent years.
BMW Z4 prototype 2018: first drive of new roadster
As well as having a completely new look with more distinctive proportions, the new Z4 adopts an electrically operated fabric hood. The new structure is claimed to weigh 60kg less than the folding hard-top arrangement of the second-generation Z4, while providing the basis for a lower centre of gravity and what BMW officials describe as “more sporting driving attributes”.
Q&A: New BMW Z4 designer, Calvin Luk
The new Z4, known internally under the codename G29, also uses a brand new platform, which will be shared with next year’s Supra in a joint engineering programme between BMW and Toyota. The design of the steel-and-aluminium structure is described as unique, although it adopts chassis, suspension and electrical components from BMW’s cluster architecture (CLAR) platform, as used by the latest 7 and 5 Series as well as the new X3, X4 and X5 SUVs and the upcoming seventh-generation 3 Series.