From what I understand, the threads are set too deep on the MSP stock shift knob to work with the Kartboy Protege shifter. I read somewhere, though, that Kartboy will make it special to fit. You'd have to ask them.
It will fit. I had no problems installing this. The only thing now is the set screws vibrate loose every once in a while. I really like the feel and the short throws. At first I was grabbing air, because it was so low. Now I'm quite used to it. Check out these photo's.