After giving the 2020 Toyota GR Supra the tuning treatment this week, it was inevitable that German tuner AC Schnitzer would work its magic on its distant sibling, the 2020 BMW Z4 Roadster - particularly as the aftermarket company specializes in modifying BMWs. For now, AC Schnitzer has focused on the range-topping M40i model, but performance upgrades for the 20i and 30i models are also planned.

In Europe, the stock BMW Z4 M40i produces 340 horsepower from a 3.0-liter turbo inline-six engine, but AC Schnitzer has increased the output to a more respectable 400 hp.

This makes it even more powerful than the US version of the Z4 M40i, which has 380 horsepower on tap as standard since it has to meet less strict emissions regulations compared to Europe. Like the standard Z4, power is sent to the rear wheels through an eight-speed automatic.

AC Schnitzer hasn't said how the power boost has affected the roadster's performance, but the increased horsepower should make it faster than the regular Z4 M40i, which will reach 62 mph from a standstill in 3.9 seconds and top out at 155 mph.

To give the Z4 a sportier appearance, AC Schnitzer has also added a quad exhaust system, as well as a front splitter and rear spoiler to increase downforce, prominent side skirts, and hood vents. As with the Supra's tuning kit, the BMW Z4 has been fitted with height-adjustable RS coilover suspension, with sporty tuning and high residual spring travel optimizing ride comfort to make the Z4 suitable for everyday use. A suspension lowering kit brings the Z4 M40i 0.9 inches closer to the ground, while the 20i and 30i can be lowered by up to 1.3 inches. Custom 20-inch wheels available in two different designs round off the exterior enhancements.

Inside, AC Schnitzer has fitted the cabin with an aluminium shift paddle set, aluminium pedals, aluminium footrest and an aluminium keyholder.