BMW discontinued the G29 Z4 in 2026 with no successor announced and no fanfare — the small two-seat roadster simply ceased to exist. The Bovensiepen family, who spent decades building Alpina into Europe’s most respected performance-car atelier before BMW acquired the brand in 2022, watched that happen and decided something needed to be done about it. Their response is the Bovensiepen Spider: a 429-hp, limited-to-99-units reinterpretation of the Z4 M40i that BMW itself never made, priced at €115,500 in Germany (roughly $134,000).
The Z4 M BMW Never Built
Operating independently under their own name, the Bovensiepen family turns a discontinued roadster into something genuinely rare.
When BMW acquired Alpina in 2022, the founding family retained the right to continue building low-volume, BMW-based cars under the Bovensiepen name. The Spider is their third project, following the Zagato — an M4 Convertible converted to a coupe — and the 05 GT, built on the M5 Touring. Starting with the Z4 M40i’s 3.0-liter B58 turbocharged inline-six, Bovensiepen reworked the intake, exhaust, and airflow to push output from 335 hp (European spec) to 429 hp, with torque climbing to 580 Nm. The wry footnote: 0–100 km/h still clocks at 4.2 seconds, matching the standard car exactly. More power, identical stopwatch.
Key specs at a glance:
- Performance: 429 hp, 4.2 seconds to 100 km/h; top speed 260 km/h standard, 295 km/h with the optional Performance Package
- Chassis: 20-inch wheels with Michelin Pilot Sport 4S rubber (255/35 front, 295/30 rear); retuned suspension with revised dampers; optional four-piston brakes with 395 mm front discs
- Design: Exterior developed with Frank Stephenson — the designer behind the modern MINI, Ferrari F430, and McLaren P1 — featuring a front splitter, enlarged wheel-arch vents, rear diffuser, and integrated spoiler
- Interior: Vernasca leather and Alcantara with a bespoke pattern; Lavalina leather steering wheel; dashboard and A-pillar available in leather or Alcantara
A Reason to Drive to Bavaria
Scarcity this deliberate is less a marketing decision than a guiding philosophy.
Those 99 units break down like a single-vineyard wine allocation:
- 40 Sapphire Black
- 25 Sanremo Green
- 20 Skyscraper Grey
- 9 Thundernight
- 5 Frozen Grey II — with other colors available on request
Each car carries an individual production plaque. Sapphire Black and Sanremo Green buyers can add cognac Vernasca/Alcantara interiors from the factory, the kind of considered detail that separates a configuration from a collectible object.
Orders are open now, with deliveries scheduled to begin in Q1 2027. The Spider is sold worldwide from Bovensiepen’s base in Buchloe, Bavaria — roughly an hour from Munich and close to the Alpine roads the car seems purpose-built to inhabit.
That €115,500 buys approximately €64,000 more than the Z4 M40i underneath it. What the premium actually purchases: Frank Stephenson’s bodywork, a numbered plaque, and a place in a production run so small that most enthusiasts will only ever encounter one in passing.
BMW ended the Z4’s story without ceremony. The Bovensipens have opened a new chapter with 99 copies, a designer who helped shape the McLaren P1, and a surname that long defined what a finely tuned BMW could be. That is not a revival. That is a statement.
