Both configurations would use a turbocharged 3.0-liter inline six-cylinder engine, but one would generate 335 horsepower, while the other would get 385. The suspicion is that this comes down to differing emissions standards between the European Union and the United States, with the former being more stringent. Or, it could reflect plans to offer the soft top with a competition package option.
The next-generation Z4 shares its platform with the upcoming new Toyota Supra. It was revealed in concept form at the Pebble Beach Concours d'Elegance, while the production version is scheduled for a world premiere next year.
Turbocharged four-cylinder engines will power both the s20i version, which will generate 180 horsepower and 200 pound-feet of torque, and the s30i, which is rated at 248 horsepower and 258 lb-ft. The company has said there won't be a Z4 M.