I partially agree/disagree with Loccusst.
I had an Unorthodox Racing pulley set on my 12v VR6.
They were well designed with the stock pulleys in mind. Voltage and relative rpm of related components were totally unaffected as the diameters remained the same.
Did it increase hp noticeably? No.
Did acceleration increase? Yes. The lighter pulleys resulted on less inertia and that car pulled like hell.
The materials used are lighter and as much material is remived without jeopardizing or compromising structural integrity. Neuspeed's version is supposedly built along the same lines.
Sorry I don't have a stock pic of the VR6 pulleys. Here's a pic of the aftermarket ones. Just picture cast iron solid ones as opposed to these. Replacing the crank, power steering, and alternator pulleys resulted in a weight diff of 93.2oz (oem)-34.2oz (aftermarket) = 59ozs or 3lbs 11 ozs
That's a lot of mass to spin in the 12v VR6 case. I'm not sure why they're using a diff belt.
Check with the guys at
www.unorthodoxracing.com and see if they plan on making one and also their thoughts on Neuspeed's design.