The 429-Horsepower Bovensiepen Spider Is Essentially the BMW Alpina Z4 M40i We Never Got
The Bovensiepen Spider is based on a BMW Z4 and comes from a company run by the family that originally founded Alpina.The turbo 3.0-liter inline-six now produces 429 horsepower and 427 pound-feet of torque, up ...
- The Bovensiepen Spider is based on a BMW Z4 and comes from a company run by the family that originally founded Alpina.
- The turbo 3.0-liter inline-six now produces 429 horsepower and 427 pound-feet of torque, up by 47 hp and 59 pound-feet.
- The Spider also wears revised bodywork and has fancier leather inside. Only 99 units will be built.
The luxury two-seat roadster segment has vanished from the U.S. The nail in the coffin came when BMW ended production of the Z4 earlier this year, closing the book on a niche that once also included the Audi TT and Mercedes-Benz SLK-class (later renamed SLC-class). But one company wants to keep that spirit alive just a bit longer, with Bovensiepen now revealing its third product, the Z4-based Spider.
If you’re not familiar with the Bovensiepen name, here’s a quick rundown. Burkard Bovensiepen founded Alpina in 1965, which grew famous for its classy twists on BMWs that focused on both speed and luxury. Over time, Alpina and BMW grew closer and closer, before BMW purchased the brand in 2022. Emerging from that transition was a new company bearing the Bovensiepen family name, and the same mantra of honing BMWs with increased performance and refinement.
The Spider is Bovensiepen’s third product, following the M4-based Zagato coupe and the M5 Touring-based 05 GT. Bovensiepen says the Spider is centered around “driving pleasure,” and it will be an extremely limited affair, with only 99 units set to be built.
As with Bovensiepen’s other cars, the design makes small but purposeful tweaks to the BMW upon which it is based. There’s a new front splitter with Bovensiepen branding, matched by new side skirts and a sporty-looking rear diffuser. The most notable change comes at the front fenders, where BMW’s simple vent has been replaced with a more dramatic arrow-shaped cutout, topped by a black trim piece reading “Spider.” The other big upgrade is a new rear lip spoiler that is significantly more pronounced than the one on the standard Z4. The Spider also rides on special 20-inch ten-spoke wheels with an intricate design, wrapped in Michelin Pilot Sport 4S tires.
There’s still a turbocharged 3.0-liter inline-six under the hood, but Bovensiepen has fiddled with it and managed to extract 429 horsepower, an increase of 47 ponies over a standard Z4 M40i. Torque has also been boosted to 427 pound-feet, up from 369 pound-feet in the stock engine. The inline-six is hooked up to the eight-speed automatic gearbox, with the six-speed manual sadly unavailable.
Bovensiepen says it opened up the intake air duct and added a new ram air channel to help improve performance, and the Spider also gets a unique exhaust setup. The Spider dashes to 62 mph in 4.2 seconds, but that estimate seems conservative given that we got an automatic-equipped Z4 M40i to 60 mph in 3.5 seconds. Bovensiepen will also offer a Performance package that includes a milled aluminum rear differential cover for improved cooling, a top speed of 183 mph (up from 161 mph), and an extra underbody reinforcement brace.
Along with the engine, Bovensiepen tuned the suspension, fitting new dampers and longer auxiliary springs at the rear, designed to make the car feel more responsive. There’s also an optional high-performance braking setup with four-piston fixed calipers on the front axle, clamping onto 15.6-inch perforated brake discs.
The cabin gets upgraded with Vernasca leather upholstery and Alcantara seat inserts, and the heated steering wheel is wrapped in Lavalina leather. Buyers can upgrade to even more expensive leather options should they choose, with the ability to wrap the dashboard in leather and the A-pillar, wind deflector, and roll bar in Alcantara.
The Bovensiepen Spider’s upgrades over a standard Z4 are subtle, but combine to create a well-equipped roadster with plenty of punch. The Spider will start at €115,500, equivalent to around $134,000 at current exchange rates, or around $64,000 more than a 2026 Z4 M40i.
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Caleb Miller began blogging about cars at 13 years old, and he realized his dream of writing for a car magazine after graduating from Carnegie Mellon University and joining the Car and Driver team. He loves quirky and obscure autos, aiming to one day own something bizarre like a Nissan S-Cargo, and is an avid motorsports fan.