is this like a modified or "chipped" ecm ?

 

It stands for "Power Commander". This is the 3rd gen of it- obviously. You are more or less correct in that it is a "chip" for your FI system. However, the primary difference is that YOU set up the map. Basically a PC is hooked up to the box and you input what other mods you have and where you would like fuel delivered in the rev range and then that is downloaded to the ECM.

I debate on one, but since mine is completely stock engine and exhaust wise, there really is no need. If you are running a can, K&N, and even different sprocket ratios, this thing can sort you out. Lotsa scrilla that I think I would rather put to a track day or 2.