German tuner AC Schnitzer has tuned the BMW Z4 Roadster, creating the ACS4 Turbo.
The modifications are designed for the range-topping sDrive35i. ECU changes mean the twin-turbocharged, 3.0-litre engine goes up from 302bhp to 355bhp.
The result is in an increased top speed of 178mph and a reduced 0-62mph dash of 4.9 seconds, a fifth of a second faster than the standard Z4. AC Schnitzer has also included a new set of springs and a sports exhaust system in the upgrade, to provide a more sporty ride and handling package
The ACS4 also has a new aerodynamic package, which includes a front spoiler, new side air vents for improved brake cooling, a two-piece rear spoiler and a chrome front grille.
It also sits on a set of 18-inch alloys, although the options list includes 19- and 20-inch wheels.
The interior has also undergone some minor changes – the Aachen-based tuner has put an aluminium cover on the iDrive controller, pedals and gearstick.
At the moment, upgrades are only available on the sDrive35i, and while there's no word yet on prices, a premium over the £37,060 list price would likely mean the ACS4 costs around the same as the £40,486 Porsche Boxster S.