Cusco Powerball Headers on a NA 4AGE 16V?

[JDMitch]

ok so i shelled out the money for the extractors and got them on and i'm pretty sure the car is slower than with the standard manifold!!!
I originally had the standard one with an A'pexi 2 1/4" resonator and a 2" stainless system with a Kakimoto muffler.
The new extractors are stainless 4-1 with about 42mm primary piping down to a 2 1/4" flange. There is a small leak in the collector where it has been rewelded poorly previously but this is only like a pinhole gap where i can feel gas coming out. Has anyone got any ideas why it feels alot slower?
It doesn't pull at all through the rev range, even at above 6000rpm.
Has anyone got any explanation or experience with this? Even a more certain way of telling if it's going better or worse besides getting it dyno'd before and after.


Thanks heaps.