Wow!
I just got back from doing the post-dyno on my car with the Kook's exhaust on and was so excited I just can't contain myself!
Wow! (It bears repeating)
The only caveat I have to mention is that my car has a 3000rpm stall in it, so getting number much below 4000rpm is near impossible on a dyno. BUT, I can tell you, the newly available amount of power and torque down low launches my car like you wouldn't believe out of the hole.
That being said, my car prior to the header install, was making 256.3rwhp and 278.6rwtq.
My car, post header install is now making....
285.7rwhp and 293.5rwtq!!
That's peak, 29hp and 15tq!!
What's important to examine is that although the peak numbers are high, there are even higher spreads in the torque and power bands throughout the curve. There's almost a 50hp spread on power at 6000rpm!!!
All in all, what a kick ass investment!!