They slightly reduce drag on the engine. I've taken the crank pulley off my '98 D16Y8 SOHC VTEC and my '95 B18C1 and neither one ever had any kind of harmonic balancer, so I don't buy much into that theory. Maybe on a larger displacement engine, or a v-style engine they would have one but I haven't seen one on my cars. Pullies are usually more of a style/look modification than anything else, but there is some performance there, just don't expect miracles.

 

I noticed a slight increase in throttle response when I went to my N1 crank pulley, but I mean nothing really that amazing.

was it worth the money...no....do I love the JDM bling factor....h: