lathewerks and twmperformance make awesome shift knobs. I'm currently using one from twmperformance which is 1.07 pounds (485 grams) vs the 170? grams of the stocker. I didn't think it would make a huge difference but it made my short shifter feel exponentially better. Plus it looks awesome! Expensive, but I've never regretted it.
side note, metal shifters get hot during the summer o_o