Underdrive pulley recommendation

[EssexPorsche]

Pup.
They were first developed with the purpose/idea to simply slow down the accessories (power steering pump, alternator, AC compressor) on a car that spends a lot of time running high revs. 986/987 PS pumps are known to overheat and leak under heavy track use.

A side benefit is that the underdrive pulley reduces parasitic drag from these components and you can measure an increase in hp and torque at all rpms between 5-10 rwhp depending on the model.

Don't have one myself (yet) but only heard good things!