I ordered one of the speed controllers last week and installed it on Friday. It appears to work correctly, but still has a totally different feel than my WoZ. I'm not sure if it is just the difference in mass between the two or not. The WoZ just feels smoother, where as the Coin Taker is more harsh, but much better after the controller install.
The installation was a piece of cake.
1. Disconnect the 2-wire harness from the circuit board attached to the side of the cabinet.
2. Cut both wires, leaving enough on both sides to install the controller.
3. Strip back both sides of the cut about 1/4".
4. On the back of the controller, you'll see all 4 pins labeled (Power -, Power +, Motor +, Motor -)
5. Connect the "Power -" to the black wire on the side with the plug you cut off the motor
6. Connect the "Power +" to the red wire on the side with the plug.
7. Connect the "Motor -" to the black wire on the motor side.
8. Connect the "Motor +" to the red wire on the motor side.
9. Plug the connector back into the board and either mount the controller to the cabinet, or tuck it away from anything metal.
This is the one I bought:
http://www.amazon.com/SMAKN%C2%AE-Motor-Control-Switch-Controller/dp/B00UURDBQ8