Nistune is good, as it refines you stock ECU.
PFC, I think would allow you to be more in depth as in if you are savvy enough to tune it yourself with the hand controller.
+ It gives you the ability to cycle through the ECU and see it for yourself.
I would consider a front mount intercooler if I had a S14A, but that's just me.
Hah! Yeah I am on NS, it's quite funny actually.