Your right, some of my statement is speculation. But the facts are: Stock case ratings were measured cold loses 5-10% once hot (as do other alts, but just depends where they rate it at to begin with) uses a smaller pulley (which may not be a bad thing) ^This was all gathered from speaking to the company. So it is pretty damn safe to assume that in order for their alternator to make anywhere near the power it is, that they are rewound. When you get your alt installed, post up the amperage numbers from engine idle and 3500rpm or what ever, and show me wrong if you would like... Just trying to help the OP before he makes a purchase one way or another.