I think you misunderstood me.the dynapack is probably the most inaccurate of all the dyno methods because you don't even have your wheels on...the more factors you have a computer estimate the more margin of error you get vs real world power delivery.
as far as the dynojet being inaccurate I trust dynojet numbers more than dynapack numbers.
then there's the mustang dyno...truly an awesome piece of equipment, it biases the rollers based on the amount of weight that is resting on them which is exactly what you want
dyno accuracy isn't the reason for street tuning though. how much power you're making has nothing to do with how well your car runs.
my point was that street tuning is a means of tuning your car under conditions other than WOT. You can't vary the load or get an accurate run at part throttle with a Dynojet (unless it has the eddy current load unit). This is true by design. You can vary the load and get a relatively accurate reading with a Mustang or a Dynapack. That's all I was saying. Also this statement is assuming you're referring to the Mustang chassis dynos and not their engine dynos.
Dynapack measuring at the hubs doesn't make it less accurate, it's just measuring the output at a different point. Would you consider an engine dyno inaccurate because it's measuring at a different point? Neither are giving you the 'real world power delivery' as you said, but that's not what a hub dyno or an engine dyno is designed to do.
Thanks for the input.