The Z4 is 147 lb-ft lighter than the stock.
The absence BMW’s M division tuning Z4 to a more efficient model, the aftermarket has stepped up to the plate. GPower can increase the roadster’s horsepower to 494 horsepower (or 368 kilowatts) using a 3.0-liter turbocharged six-cylinder engine. This is in contrast to 335 HP (250 kW), which is the European-spec M40i-grade , or 382 HP (285 kW), for the American-spec version. In stock form, torque is 516 pound-feet (706 Newton-meters) instead of 369 (500 Nm), in Europe and the U.S.
G-Power claims the tuned Z4 can reach speeds of 62 mph (100 km/h) in 3.9 seconds, as opposed to 4.5 seconds for the factory trim. G-Power estimates that the roadster can travel over 186 mph (300 km/h), as opposed to the electronically limited 155mph (250 kph), which is the case off the showroom floor.
Find out How Much Power the Z4 has:
These upgrades include G-Power Performance Software V3 which costs EUR1,639 (or $1,851 at current exchange rate) and remaps your engine control unit. For EUR500 ($565), the top speed increase is possible. Modified turbos are available for EUR2,899 (€3,275) and upgraded intercoolers with greater cooling capabilities cost EUR1,471 (1,662). For EUR1,639 ($1,851), you can get better breathing with flow-optimized downpipes that have sports catalytic convertors.
G-Power’s results are quite impressive considering that Dahler, the tuner from Switzerland, can’t make the car as powerful. The stage 1 kit increases the Z4’s power to 402 horsepower (300 kW), and 457 lbft (620Nm), while the stage 2 version boosts the car to 435 HP (324 kW) & 472 lbft (606 Nm).
G-Power’s main focus is on improving the Z4’s performance. However, the company can modify the look of the roadster with a set 20-inch wheels with five pairs dual spokes. They are 9 inches wide at the front and 10.5 inches back. They retail for EUR6,681 (or $7,545).