rdub, You need to have a picture stored on your computer that is 80 x 80 pixels or whatever than you use the avatar under your control panel, click on browse to find it.
Yes you need to unscrew the allen head bolts in the motor heatsink and rock the motor while pushing from underneath. It should come out. If your wires are sodered to the motor from your speed control then you need to unsoder them. Unscrew the motor plate on the front of the motor and reattach to the new motor. Pay attention to which tab on the motor is Positive and resolder the wires.
Put the motor clamp(heatsink) back on and adjust your gear mesh, Then get ready to go real fast!