German tuner dials up output on the 3.0 liter twin-turbo to 405 PS (298 kW / 400 bhp) and 539 Nm (398 lb-ft) of torque.

German tuner Kelleners Sport has turned the BMW Z4 sDrive35is into a real rager.

The power upgrade involves a tuning of the 3.0 liter twin-turbocharged inline six-cylinder unit up to an output of 405 PS (298 kW / 400 bhp) and 539 Nm (398 lb-ft) of torque. That's quite a gain over the already impressive series output of 340 PS (250kW/ 335 bhp) and 450Nm (332 lb-ft) of torque - 500Nm (369 lb-ft) with overboost.

Wheels are available in 19-inch and 20-inch dimensions in either Hamburg or Berlin rims. Special lowering springs reduce the ride height of the Z4 by 20 mm at the front axle and 10 mm at the rear.

On the inside, the tuner adds a three-spoke sport steering wheel, aluminium pedals and foot rests along with velour floor mats. Bespoke interior finishes in leather with wood trims are also on offer by individual customer request.

Gallery: BMW Z4 sDrive35is by Kelleners Sport