I don't understand the title... the topic has been beaten to death (more than any other mod for the VQ)... if you turn your settings to "show all threads" and do a search, the title of this thread will undoubtedly change.

After you read the billions of posts, you will find there is no conclusion either way pro or con... for every opinion that says it’s no good there will be a user that says it is.

Literally flip a coin and you will get similar results as research opinions here and on my350Z.

Fact.

 

I've had pulleys installed for a while, both on my 03 auto, and my newer 05 6MT and they make a significant difference, not to mention the stock ones are a good 10 pounds, and the UR Pullies I got are under 2 pounds. Its a pretty big difference, not to mention you can rev slightly faster, but not quite what a flywheel would do. I'd say go for stock size UR. Underdrive can mess up your components like water pump and alternator, cuz they spin at a slower speed. Definitely go for the Pullies tho! I have some clips on Youtube of them too www.youtube.com/user/ackilles85