haha I'm going to be installing the headers tomorrow
I've no personal experience with ESS tunes, but I'm sure they hold their own ground nicely. All these non-FI, non-custom (no live dyno runs while tweaking ECU) tunes are pretty much the same thing from what I understand
The "gains" I experienced from my personal tune with AA was a delay in the torque curve drop and drops with less severity than stock. This was what yielded the higher peak hp's.