Barely four months after the final BMW Z4 rolled off the production line, the roadster is back – sort of. Bovensiepen, the company established by the family behind Alpina, has unveiled the Spider, a reworking of BMW's recently discontinued two-seater.

Based on the Z4 M40i, the Spider retains its turbocharged 3.0-litre B58 straight-six and rear-wheel-drive layout, but revisions to the intake and exhaust lift output to 429bhp and 428lb-ft. Just 99 examples will be converted at the former Alpina works in Buchloe..

Rather than attempting to create the M version this generation of Z4 never received, Bovensiepen has followed the old Alpina philosophy: more performance, no more aggression. Accordingly, the Spider sticks with the ZF eight-speed automatic rather than the late-production six-speed manual that arrived under the Handschalter banner.

Bovensiepen Spider - rear
Bovensiepen Spider - interior

Claimed performance is 0–62mph in 4.2sec with top speed limited to 162mph. Tick the optional Performance Package and that rises to 183mph, with the pack also adding a larger finned aluminium differential cover and an underbody V-brace.

The chassis has been reworked too. Newly calibrated dampers gain greater low-speed compression, while longer auxiliary springs feature at the rear. Staggered 20-inch forged wheels are wrapped in Michelin Pilot Sport 4 S tyres (255/35 front and 295/30 rear), with an optional high-performance brake package adding four-piston fixed front calipers and perforated 395mm front and 345mm rear discs. Bovensiepen quotes a DIN kerb weight of 1585kg.

Frank Stephenson, fresh from the 05 GT, has been commissioned to rework the exterior. The Z4’s basic proportions remain, but a new front splitter, vented front wings and deeper side skirts lead to a more pronounced boot spoiler, rear diffuser and quad exhaust outlets. It’s recognisably related to the donor car without resorting to the visual aggression of a conventional M makeover.

Bovensiepen Spider - alloy wheel close up
Bovensiepen Roadster - Skyscraper Grey

Inside, Vernasca leather and Alcantara feature as standard, with Lavalina used on the steering wheel. Bovensiepen’s in-house saddlery opens the door to rather more elaborate requests, including a full Lavalina interior and bespoke colours, materials and embroidery. The 99 are pre-allocated across five metallic finishes: 40 Sapphire Black, 25 Sanremo Green, 20 Skyscraper Grey, nine Thundernight and five Frozen Grey II. Paint to sample is available on request, and each car carries a numbered plaque.

While Alpina and BMW always enjoyed a close relationship, Andreas Bovensiepen's association with BMW roadsters goes deeper. "Ever since I was part of the BMW Z8 development team at BMW in Munich in the late 1990s, purist roadsters have fascinated me," he says. Alpina later produced the Z4-based Roadster S, the closest spiritual ancestor to the new Spider.

Orders are open now, with the Spider priced at €115,500 in Germany including 19 per cent VAT – around £99,000 – and first deliveries due at the end of Q1 2027. UK pricing and availability have yet to be announced.

Bovensiepen Spider - exterior duo