Bovensiepen Spider launch: 435hp BMW Z4 roadster details

Bovensiepen has revealed the Spider, a limited-production two-seat roadster based on the BMW Z4 M40i, with production restricted to just 99 hand-built cars. Orders are open now and first deliveries are scheduled for the end of the first quarter of 2027, so this is aimed at buyers looking for a very limited roadster rather than a regular Z4 alternative.

Bovensiepen Spider design and dimensions

The Spider keeps the BMW Z4's long-bonnet, rear-set-cabin roadster layout but gets its own exterior treatment. It has a gloss-black front splitter with twin tips, front-fender vents, side skirts, a rear diffuser, an integrated rear spoiler and 20-inch forged wheels.

It measures 4,334mm long, 1,864mm wide and 1,304mm tall, with a kerb weight of 1,585kg. The 99 cars will also be split across five colours:

• 40 in Sapphire Black
• 25 in Sanremo Green
• 20 in Skyscraper Grey
• 9 in Thundernight
• 5 in Frozen Grey II

What the Spider gets inside

The basic cabin layout remains close to the BMW Z4, but Bovensiepen has changed the materials and personalisation options. Standard equipment includes Vernasca leather, Alcantara seat panels, a Lavalina leather steering wheel, a heated steering wheel, Comfort Access and a Harman Kardon surround-sound system.

Buyers can add full-leather upholstery, a leather dashboard and Alcantara trim for the A-pillars, wind deflector and roll-bar cover. Personalised headrest embossing and embroidery are also available, while every car gets a numbered production plaque. Boot space is 281 litres.

435hp B58 engine and 295kph option

The 3.0-litre turbocharged B58 inline-six produces 435hp and 580Nm, with drive going to the rear wheels through an eight-speed ZF automatic. That is 95hp and 80Nm more than the BMW Z4 M40i's 340hp and 500Nm output.

The Spider is claimed to reach 100kph in 4.2 seconds and has a 260kph top speed. An optional Performance Package raises the top speed to 295kph and adds larger differential cooling fins, an underbody V-brace, revised dampers and longer rear auxiliary springs.

Would you consider a 99-unit Spider over a standard BMW Z4 M40i?