underdrive pulley
 

It seems like a fair number of members have installed the underdrive pulleys. since there has been a significant period of time, I would be interested to know if anyone has found it actually has proven to be advantageous and also if anyone has had negative results or none at all.

I've had mine on for a year and have no issues including when we see 110 F plus. Essentially it gives you a little more power that you barely feel and very quickly get used to. Is it worth it. For the small amount of money I'd say sure. Without a serious engine upgrade the Boxster is never going to be a powerhouse.

I've had mine for two years. No negatives - power steering, water pump, and A/C work exactly as they always did. Power increase is only noticeable (to me) on the track so as Porsche9 said, its there but you barely feel it or get used to it very quickly. Worth it? Yes, +5hp is always welcome for such a low cost. Wish I could find 20 more things that cost so little, have no drawbacks, yet yield +5hp each. :)

4 years, 100ish track days, AC still blows cold. No issues.