either way it shouldnt clunk. but in actuality rubber will be more likely to clunk since it is soft and the bars could more easily bully it into hitting metal on metal. the urethane will produce a slight squeek if not greased and a lil bit more road feel will come out of it when the sway bar is being moved around . but urethane is the shiznit

 

Gabe is installing some TRD springs for me tommorow-I'm going to wait until they settle before I measure what size of endlinks I should install. After calling Energy Suspension they advised me to wait and measure the suspension once the springs settle and then purchase the correct size endlinks. Well another month of waiting won't kill me

 

Odds are very good that there is more weight with the newer sway bar. The key to a better sway bar is one that flexes less. To prevent the flexing, either stronger metals are used, larger diameters, or if it was once hollow, it's now less hollow or not hollow at all, or a combination of the above.

Any way you look at it, your adding more mass, hence adding more weight, UNLESS it's some different materials that's lighter but also has better structural strength. I've been racing cars for a number years and have not heard of any other special materials where you can save weight on swaybars. If there was, it's very likely that that bar would cost about 50% more too, depending on the weight reduction.

Cheers,