the knob is almost impossible to remove. i removed my spyhunter shifter from the control panel by using a small punch and hammering out the tiny pin that holds the shifter shaft into the shifter body.
at the end of your spyhunter steering wheel, where the sprocket is, there should be a small potentiometer. you will see it turn when u turn the steering wheel. the spyhunter pot is a 1k pot but its possible to replace the pot with a 5k pot and hack it with a dual strike controller. do a search of the boards for more info on the dual strike.