Dalek vs soldering iron

[modbom]

I'm new to robotics. and I'd like to modify this toy I recently bought
http://www.whona.com/mm5/merchant.mvc?S ... ode=cotoys
There's lots of empty space inside and I'd love to try some modifications to it. I'd like to start by replacing the loud motors with something quieter. Maybe from here
http://www.hobbyengineering.com/
I would love to take advantage of the basic stamp starter kit I bought and do something more too. Does anyone have any suggestions that might help me get started?