Al, I'm no expert, but I'd guess the intake side is what's holding you back now. I remember reading something which slated a K&N filter over a standard one, although that was for a yank tank and not a WRX. Perhaps some sort of Cold Air Intake is where its at.
My engine plans for next year are quite similar to what you've done, with the exception of the headers, so your results give me something to aim at.
OH, I forgot to say - those are good figures. You shouldn't be disappointed.