The BMW Z4 is back, at least briefly, in the form of a new Bovensiepen Spider that revives the roadster with more power, sharper handling and a redesigned exterior. The special model is based on the BMW Z4 and focuses on lightweight performance, open-air driving and a more dramatic design.
A New Life for the BMW Z4
Production of the BMW Z4 ended this past spring, around the same time production of its Toyota GR Supra sibling also came to an end. Both cars were produced by Magna Steyr in Austria, leaving BMW without a true sports car in its lineup.
Now, the Z4 has returned in a limited revival from Bovensiepen, the new name for Alpina’s original tuning outfit. Alpina became part of BMW in 2025 in name only, while the actual tuning business remains with the Bovensiepen family, the founders of Alpina.
Bovensiepen previously introduced a Zagato-rebodied BMW M4 in 2025, followed earlier this year by the BMW M5 Touring-based 05 GT. Its latest creation is the BMW Z4-based Spider, designed to preserve the joy of driving through light weight, sharp handling and open-air fun.
More Dramatic BMW Z4 Design
To give the Spider a more distinctive appearance, Bovensiepen turned to the design house of Frank Stephenson, the designer of the McLaren P1 and the first BMW X5.
The exterior receives a new front splitter, distinctive wheel-arch vents in the front fenders, new side skirts and a rear diffuser. These aerodynamic elements are finished in gloss black, which Bovensiepen intends to establish as a design signature.
A body-colored ducktail spoiler further stretches the car’s silhouette and gives it a sportier appearance. Custom 20-inch forged wheels complete the exterior design.
429 Horsepower From BMW’s B58 Engine
Under the hood, the Bovensiepen Spider uses BMW’s B58 turbocharged 3.0-liter inline-six. The engine is tuned to produce 429 horsepower and 428 pound-feet of torque.
That represents an increase over the 382 hp and 369 lb-ft produced by the Z4 M40i, the range-topping version of the last Z4. In the Bovensiepen Spider, the power-to-weight ratio means each horsepower has less than eight pounds to carry.
The additional power comes from Bovensiepen’s lightweight exhaust system, a new air intake with improved breathing and a new ram-air channel, along with an engine tune. The resulting output matches the 429-hp figure of the GR Supra Final Edition sold in Europe and Japan.
An available Performance Package adds a custom rear differential cover with larger cooling fins to reduce stress on the differential during high-speed driving. It also adds an underbody V-brace designed to increase rigidity.
Rear-Wheel Drive and 183-Mph Top Speed
Power continues to reach the rear wheels through the donor car’s eight-speed automatic transmission. Under optimal conditions, Bovensiepen says the Spider can accelerate from zero to 62 mph in 4.2 seconds.
That figure could prove conservative, given that BMW’s own figure for the less powerful Z4 M40i is 3.9 seconds from zero to 60 mph.
The Spider has a standard top speed of 162 mph, while the Performance Package raises the figure to 183 mph.
Upgraded Chassis and Interior
Bovensiepen also upgraded the chassis to handle the additional power. The changes include longer auxiliary springs at the rear and retuned dampers intended to provide sharper responses and improved grip.
Grip is further supported by Michelin Pilot Sport 4 S tires measuring up to 295 millimeters wide at the rear and 255 millimeters at the front. A high-performance brake package with four-piston front calipers and larger rotors is also available.
The interior receives its own set of upgrades, including Vernasca leather and Alcantara upholstery, a Lavalina leather steering wheel and a range of standard comfort features.
Buyers can also choose a fully leather interior, along with personalized embroidery or embossing, giving the revived BMW Z4-based Spider an added level of customization.
