Ok, so really... what is this good for. The product description is a bunch of marketing fluff.

http://www.namotorsports.net/detail...._cd/NS62.02.65

Are there any real gains from this?

 

By using a smaller pulley on the crank the engine turns the pulleys on the alternator, water pump, and A/C slower. The Neuspeed pulley may also be lighter in weight than the stock pulley, which will put less demand on the engine. In theory, the smaller pulley may free up a few horsepower by reducing the drag on the crank, I don't have this on my A3 so I'm not sure how noticeable it is. Keep in mind that by turning your accessories slower, you are decreasing their output. Your engine may not cool as efficiently, your alternator will produce less amperage, and your A/C performance may suffer. I'm not sure if the A3 has a traditional, belt-driven power steering pump, but if it does then it would also under-perform. I had an underdrive pulley on my Blazer before I got the A3, but that kit also came with a smaller pulley for the alt, keeping it spinning at the same speed. Also, I had ditched my clutch fan for a much more efficient electric fan, so my engine cooling was already better than stock and it also helped keep the A/C cold. On the Blazer it produced a bit quicker acceleration, particularly when I was cruising and needed to accelerate to pass, but I didn't notice any top end gain. Of course the A3 is an entirely different beast. Personally, this is one mod I am going to skip on my A3 primarily because I do not want to negatively affect engine cooling and electrical output.

 

^^^ YEP!