Bovensiepen, the new marque set up by the founders of Alpina, has turned the BMW Z4 into a 431bhp collector special called the Spider.
The brand's third car – after the £320k Zagato coupé and £144k 05 GT estate – is its first convertible, but can trace its roots back 20 years to the Z4-based Alpina Roadster S that its creators produced in their previous guise.
Just 99 examples will be produced, with deliveries beginning in early 2027, but the Spider is priced well below its range-mates, at the equivalent of £99,000 in Germany - roughly the same as a new BMW M4 convertible.
The firm says that cars are constantly becoming "bigger, heavier and increasingly influenced by SUV designs", and as a result "a vehicle class that for decades epitomised the most immediate formof driving is disappearing: the lightweight, two-seater roadster".
Pledging to preserve this endangered species, Bovensiepen has overhauled the most recent Z4 – which bowed out of production earlier this year – "entirely in the spirit of 'fine driving'".
It is based on the top-spec Z4 M40i, with output from its 3.0-litre straight six ramped up substantially to 429bhp and 428lb ft.
That's enough to give a 0-62mph time of 4.2secs and a maximum speed of 183mph - making it quicker than any previous iteration of Z4.
Modifications to the intake system, meanwhile, mean the engine can "breathe freely", and the re-engineered exhaust system has been optimised for flow while "at the same time delivering an exhilarating, sporty sound".
Cooling has been improved, too, to ensure the Spider can always offer peak performance, while an optional Performance Pack brings enhanced heat management for the differential, to boost its performance in high-load situations.
The Spider rides on retuned dampers for improved responsiveness, supported by the sticky Michelin Pilot Sport 4S tyres wrapped around the lightweight forged wheels. The brakes can be optionally upgraded to high-performance items, too.
The Z4 was latterly available with a six-speed manual gearbox, but the Spider comes with the standard ZF eight-speed auto.
In characteristic Alpina/Bovensiepen fashion, the Z4's interior has been retained but retrimmed in a selection of upmarket materials, including Vernasca leather for the seats, Lavalina for the steering wheel and Alcantara for the windscreen surround.
