Apparently I have some reading to do... I kinda get what
hawk02 is saying but I'm going to need to understand and compare the standards before I really understand.
It seems from the explanation that both standards are attempts to provide a universal point of reference that can be compared with any other dyno, provided they use the same protocol. This is accomplished by conducting the measurements under a specific set of controlled conditions. The difference between the two apparently lies in the correction factors used. Does that sound about right?
In order to determine the performance impact of any modification with any degree of certainty you would obviously want to use the same speed shop, same dyno and settings, and same tuner if possible. Although theoretically a shop in CA using the same dyno with the same CF should produce the same results as one in NC it would seem that this is seldom the case.
Still, given these caveats it would be interesting to see what kinds of numbers others are pulling.
--Cal