I dunno if it works. But I've talked to Mike Kopstain a whole bunch about it, and many other SHO things, and from waht I gather it would have a positive effect. On the v6 SHO's i think you'd see more at night or when the ACC loads are high. For me I'm still kinda torn between UDP's or trying out a VAK.
did I get the wrong idea? It says on that site that it shuts off your accessories.
"On the front end of your engine is the power steering pump, A/C compressor, alternator, and water pump. These accessories are spun by a belt that wraps around a pulley attached to each accessory. The belt is also wrapped around the crank pulley, which powers the rest of the pulleys, and ultimately, the accessories. These accessories require horsepower to be spun.
A lot of people use under drive pulleys, which utilize a larger crank pulley, essentially causing all of the accessories to spin slower, which frees up some horsepower. While under drive pulleys are great, they can't free up all of that power. If they did, you wouldn't have any steering assist, any air conditioning, and your battery wouldn't charge.
The alternative is to shut these accessories off for a short amount of time, specifically when accelerating, when you need the power the most. This is what the V.A.K. does, and it makes for a fun drive. "