New to Build

Hello I am new to building a router! The mechanical end I understand, but the electronics that's a different story. I'm sure this has been asked before, but what electronics do I use to control the router! If I buy the PiBot kit is that all I need + the power supply? What controls the spindle speed or does it run full rpm all the time? Is there a complete kit other than the PiBot?
Thank you for your input!
Brian