Production of the BMW Z4 finally came to an end this past spring, with the car’s Toyota GR Supra sibling biting the dust around the same time (both were produced by Magna Steyr in Austria). This means BMW is now left without a true sports car in its lineup, something we hope will be rectified at some point. But out of nowhere, someone has brought the Z4 back from the dead, albeit briefly, with some extra special sauce.
A Z4 Revival With Alpina’s Special Sauce
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You might not be familiar with the name Bovensiepen, but any fan of BMW will know the company in its previous form. You see, Bovensiepen is the new name for Alpina’s original tuning outfit. Alpina itself became part of the BMW fold in 2025, though in name only. The actual tuning business remains with the Bovensiepen family, the founders of Alpina.
Bovensiepen already launched a Zagato-rebodied BMW M4 in 2025 and followed it up earlier this year with the BMW M5 Touring-based 05 GT. The latest addition to the lineup is the BMW Z4-based Spider, which, according to its makers, is meant to preserve the joy of driving by focusing on a light weight, sharp handling, and open-air fun.
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Naturally, a striking design is also important for any sports car, and while the Z4 is no doubt a handsome roadster in stock form, Bovensiepen called on the design house of McLaren P1 designer Frank Stephenson (he also designed the first BMW X5, by the way) to deliver something more dramatic.
The changes include a new front splitter, distinctive wheel-arch vents in the front fenders, plus new side skirts and a rear diffuser. Those aerodynamic features are all finished in gloss black, which is to become a design signature of Bovensiepen. In addition, the designers also added body-colored ducktail spoiler that creates a more elongated, sportier silhouette, while custom 20-inch forged wheels complete the look.
But What’s Under The Hood?
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Like any true roadster, the Bovensiepen Spider targets power-to-weight rather than outright horsepower. That doesn’t mean the car doesn’t feature any upgrades under its long hood. Pop it, and you’ll find BMW’s familiar B58 turbocharged 3.0-liter inline-six, but tuned here to deliver 429 horsepower and 428 pound-feet of torque. That’s a healthy jump over the 382 hp and 369 lb-ft the engine delivers in the Z4 M40i, the range-topping variant of the last Z4, and it means that in the Bovensiepen Spider, each horsepower has less than eight pounds to carry.
The extra power is courtesy of Bovensiepen’s own lightweight exhaust system, a new air intake that breathes better and includes a new ram-air channel, and a tune that delivers exactly as much power as the GR Supra Final Edition did in Europe and Japan. An available Performance Package adds a custom rear differential cover with larger cooling fins, designed to reduce stress on the differential during high-speed driving. The package also includes an underbody V-brace that adds rigidity.
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Drive remains to the rear wheels only, via the donor car’s eight-speed automatic transmission, and in optimal conditions, owners can expect zero-to-62-mph acceleration in 4.2 seconds. That’s likely a conservative figure, though, as BMW’s own figure for the less powerful Z4 M40i is 3.9 seconds to 60 mph. The top speed is 162 mph as standard and 183 mph with the Performance Package.
Chassis And Interior Upgraded, Too
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The chassis is also optimized to make the most of the extra power. The list of upgrades includes longer auxiliary springs at the rear and retuned dampers aimed at delivering sharper responses and improved grip, helped by Michelin Pilot Sport 4 S rubber measuring up to 295 millimeters wide in the rear (255 in the front). A high-performance brake package with four-piston front calipers and larger rotors is also available.
Inside, Bovensiepen has given the Spider the same attention to detail, with Vernasca leather and Alcantara upholstery, a Lavalina leather steering wheel, and a range of standard comfort features. Buyers can also opt for a fully leather interior, along with personalized embroidery or embossing.
CarBuzz Insight – Why This Matters
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Traditional sports cars are becoming a dying breed, particularly open-top models like the Z4. As automakers continue to prioritize SUVs, EVs, and more practical performance cars, it may be companies like Bovensiepen that keep these traditions alive. The Spider shows there is still room for a small, focused roadster built around the simple joy of driving.
Bovensiepen plans to limit production to just 99 units, with prices in Europe starting at 115,500 euros (approximately $134,000). Availability in other markets is yet to be announced.
