I dont want to say I told you so. Everything comes down to the calibration of the dyno. You will not be able to calculate results for this type of thing, not to mention heat soak makes a HUGE difference in this car. People haven't realized this yet, but I lost as much as 15hp due to a 30 degrees temp difference...
Regardless, those are excellent numbers, congrats on being the first Z on the forums over 300whp. That is simply amazing.
I am going to have the same setup + headers. Hopefully by next week. We will see if I end up making as much power at least.
Really really glad you are on these forums Ben, you are very helpful.