This week ABS is releasing a wheel speed sensor 32034 for the 2015 models Smart ForTwo and ForFour. 32034 is the sensor for the front axle. On the rear you will need sensors 32035 and 32036.
For these cars ABS has a full range of brake parts; discs, pads, splash panels, drums, shoes, etc. Steering parts for both models area also available and although both cars look different they share a lot of these parts.