Like the newest BMW models, the roadster will feature a similar interior design with the latest iDrive system featuring a freestanding touchscreen. An updated control section near the gearshift features flatter buttons and what appears to be a larger knob with a touchpad on top. The steering wheel is also new and looks similar to the one found on the new 5 Series sedan .

Inside the cabin, there's a sheet taped on the dash that shows some key info, including the Z4 successor's model code, G29, and the engine found in this prototype, which is the new B48 2.0-liter turbo-four used in everything from the Mini Cooper S Hardtop to the BMW 530i. This particular model features a version, dubbed the "S20i," rated at around 194 hp and 236 lb-ft of torque. For the U.S., however, it's likely that we'll receive the 30i variant, which is the same engine rated at 248 hp and 258 lb-ft in the 230i, 330i, and 530i. In addition to the four-cylinder variant, the Z4 successor should also include a six-cylinder-powered M40i model that may utilize the same 335-hp 3.0-liter turbo I-6 found in the M240i and 540i. Although the prototype we spied featured a six-speed manual transmission, expect the U.S.-spec model to come exclusively with the ZF-sourced eight-speed automatic transmission. If a row-your-own option does become available in the upcoming Z4 successor, it'll likely be limited to the base four-cylinder variant.