Also JFTR, current SAE Net and Certified Horse Power numbers are done with all engine accessories and stock exhaust in place.
http://en.wikipedia.org/wiki/Horsepower
SAE net power
In the United States, the term bhp fell into disuse in 1971-72, as automakers began to quote power in terms of SAE net horsepower in accord with SAE standard J1349. Like SAE gross and other brake horsepower protocols,
SAE Net hp is measured at the engine's crankshaft, and so does not account for transmission losses. However, the SAE net power testing protocol calls for standard production-type belt-driven accessories, air cleaner, emission controls, exhaust system, and other power-consuming accessories. This produces ratings in closer alignment with the power produced by the engine as it is actually configured and sold.
SAE certified power
In 2005, the SAE introduced "SAE Certified Power" with SAE J2723.[20] This test is voluntary and is in itself not a separate engine test code but a certification of either J1349 or J1995 after which the manufacturer is allowed to advertise "Certified to SAE J1349" or "Certified to SAE J1995" depending on which test standard have been followed. To attain certification the test must follow the SAE standard in question, take place in an ISO9000/9002 certified facility and be witnessed by an SAE approved third party.