There are a few other bottle-necks that need to be taken care of too.
I am running the stock exhaust/cat from the MSDS to the catback system. That will be replaced with 2.25" piping, a nice SS flex pipe, and a hi-flow cat. I can imagine this alone worth a few higher end HP.
Although a miniscule bottle-neck, I am running the Injen MAF adapter (WHICH SUCKS), so that will be upgraded, as well as a new larger filter.
But as Demon said, it can only get better (or until the 19's are maxed

)