well, the knob I have is true carbon fiber. the inside is lead based(ass all nice shifters are.

The lead on the inside would be sealed with a plasti-coat( I have like 84 bottles of it). Its the same stuff used on tool handles. That way no risk of exposer to the lead. Then a plastic cap will be added on top of that.

I also have a cheap ass momo knock-off that I my try it with just to see if i like it.

As for being weighted it allows for more of a "throw" vs. a push into each gear. It cuts down the risk of missing a gear due to the weight helping you(unless you just cant drive.)

Thanks for the info and opinions,
-Mike