BMW Z4 M enthusiasts have a new option: the Bovensiepen Spider, a limited-run roadster that pushes the base model’s performance to 429 bhp.
Limited-edition specs and pricing
Only 99 units of the Spider will be built, with deliveries slated for early 2027. In Germany the price is set at the equivalent of £99,000, matching the cost of a new BMW M4 convertible. The model follows Bovensiepen’s earlier releases, a £320k Zagato coupé and a £144k 05 GT estate.
The Spider is based on the top-spec Z4 M50i, but the 3.0-litre straight-six has been tuned for higher output. Power rises to 429 bhp and torque to 428 lb-ft, delivering a 0-62 mph sprint in 4.2 seconds and a top speed of 183 mph, faster than any prior Z4.
Mechanical upgrades and optional equipment
Modifications include a freer-flowing intake, a re-engineered exhaust tuned for sound, and upgraded cooling to keep the engine at peak temperature. An optional Performance Pack adds heat management for the differential during high-load driving.
Chassis work features retuned dampers and lightweight forged wheels wrapped in Michelin Pilot Sport 4S tyres. Customers can elect high-performance brakes and an optional performance exhaust, though the car ships with a standard ZF eight-speed automatic; the previous Z4’s six-speed manual is not offered.
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The interior retains the Z4 layout but receives new trim options such as Vernasca leather seats, a Lavalina-wrapped steering wheel and Alcantara around the windscreen. The Bovensiepen Saddlery program lets buyers add custom embroidery, Alcantara boot lining or personalised headrests, echoing the bespoke services of Bentley’s Mulliner.
Why the Spider matters for road-ster enthusiasts
Bovensiepen’s founders argue that modern cars are getting larger, heavier and more SUV-inspired, threatening the “lightweight, two-seater roadster” segment. By reviving the Z4 platform, the Spider aims to preserve that driving experience.
In practice, the limited run offers a rare chance for collectors to own a high-performance convertible that remains relatively affordable compared with other exotic specials. Its blend of Alpina heritage and BMW engineering could appeal to drivers who value raw engagement over outright luxury.
According to the company’s filing, the Spider’s cooling system has been refined to maintain performance under sustained high-speed conditions, a detail that may matter on track days or spirited weekend runs.
