I would not say the Tungsten stylus is a perfect fit for a CX00. It sticks out a bit far and has an ackward look on these units.
However, you can make the Tungsten stylus a perfect replacement. The black cap can be removed, albeit with great difficulty. You use a couple of pliers with the black cap and stem wrapped with a cloth or paper towelto protect them from damage. Then pull and wrench like hell. Be sure one plier holds the thin stem part of the spring load and the other pliers on the black cap. DO NOT HAVE THE PLIERS HOLD THE MAIN STEM OF THE STYLUS OR YOU WILL COMPLETELY DESTROY THE STYLUS. Once the black cap comes off, use a hack saw to remove 2-3 millimeters from the stem and also the same amount from the black cap. Then place the black cap back on. You need to wiggle it on with quite a bit of force. Voila a stylus with a perfect fit.
After I made mine for my C760, it is probably the best stylus I have owned for any of my Zaurii. The spring loaded top is very nice.