BMW Killed The Z4, But Alpina’s Founders Just Brought It Back With 429 HP
Bovensiepen’s third model is based on BMW’s recently departed Z4 roadster. The donor Z4 M40i’s 3.0-liter inline six is boosted from only 335 hp to 429 hp. Frank Stephenson Design provides subtle styling mods, including rear spoiler. The final BMW Z4 rolled off the Graz, Austria, production line in May, and while there are still cars hanging around dealer lots, your chances of speccing one to your taste are over. Or so we thought until we learned about the Bovensiepen Spider. If you’re not familiar with the Bovensiepen name, you are almost certainly familiar with the four-wheeled work of the people behind it. The Bovensiepen family set up the Alpina brand in the 1960s and did such a great job of enhancing BMW cars in the intervening years that BMW bought it out, the final transfer taking place at the start of 2026. Related: Alpina’s Founders Built A 790-HP BMW M5 Wagon That Looks Like A Lease Special But it l...