The Racing Wheel itself is slightly larger and adds some rubberized grips at the nine and three positions, not only making the controller less likely slip in long gaming session-induced sweaty palms, but also a bit more comfortable in those same lengthy races.
On the back side of the peripheral is a battery case compartment that, instead of holding a power supply, provides a port to plug your MotionPlus Sensor into. The plug's other end comes out on the right side of the Wii-mote's cradle in order to provide communications between the two units. By moving the MotionPlus area to a central location on the back of the wheel, Memorex not only keeps any balancing issues at bay, but also prevents the sensor from awkwardly sticking out of one side of the wheel.
Similar to Nintendo's steering wheel, there is a larger button resting on the other side of the Wii-mote's (B) Button, but unlike the first-party peripheral, this button is spring-loaded on its own instead of relying on the controller's button's force to push back. Theoretically, this means that the button is more responsive, but I didn't really notice that much of a difference.