V8-Swapped BMW 1 Series Convertible Listed for $75,300
Builder grafted an M3 S65 engine and widebody panels onto a soft-top 120i chassis BMW never produced from the factory.
A one-off BMW 120i convertible packing a V8 engine from an E90 M3 is listed for sale on PistonHeads Classifieds at £56,500, roughly $75,300. The UK-based build merges the widened bodywork of the factory 1M coupe with a soft-top chassis BMW never offered in high-performance form.
BMW produced exactly 6,309 examples of the 1M coupe between 2011 and 2012. Every single one left the Leipzig assembly line as a fixed-roof two-door powered by the N54 twin-turbocharged inline-six. Buyers wanting open-air driving were restricted to the standard 135i convertible or the base-model 120i, neither of which received the aggressive suspension geometry or flared fenders reserved for the M division’s entry-level project.
Independent garages have spent years bridging that gap. Most V8-swapped 1 Series builds target the rigid coupe platform or the E87 hatchback. Converting an E88 convertible introduces structural complications. Dropping a naturally aspirated S65 V8 into a chassis designed for a four-cylinder requires extensive reinforcement to prevent the scuttle panel and A-pillars from flexing under the 414 horsepower generated by the 4.0-liter engine. That output exceeds the original 1M’s 335 horsepower by nearly 25 percent.
PistonHeads first flagged the listing, noting it as one of the few modified 1 Series convertibles currently circulating in the European market. The builder started with a 120i rather than the more common 135i donor car, stripping the low-output base model down before grafting on the 1M exterior panels and mounting the M3 drivetrain.
The asking price sits well above current market values for unmodified examples. Clean 1M coupes trade between $45,000 and $65,000 in the United States depending on mileage, according to recent Cars & Bids auction results. Standard 120i convertibles typically change hands for a fraction of that figure. Factory-built E93 M3 convertibles — which came equipped with the same S65 V8 from the start and featured reinforced chassis bracing engineered by BMW M — routinely sell for less than this custom conversion.
BMW discontinued the 1 Series convertible after the 2013 model year, replacing it with the 2 Series lineup. The automaker never revisited the concept of a compact M-performance ragtop, eventually shifting the entire M2 range exclusively toward fixed-roof coupes.
