Honda engines come pretty well tuned from the factory, the only real power adders are things that would be too expensive, impractical to mass produce, not EPA friendly, or would sacrifice quality or comfort. The power steering and alternator were designed to be driven at a certain speed. If it were a good idea to drive them at a lower speed than they are, I'm sure Honda would have done that, especially when the result is more horsepower.
I seriously doubt that Honda just messed up and made their pulleys the wrong size, and now some aftermarket company has found the perfect solution. Honda did what they did for a reason. I'd trust the compitence of Honda engineers over some aftermarket company any day.