The ecu has a learning mode built into it. In the , I believe april, edition of sport compact car magazine they were getting a weird hp# on their project wrx. So they reset the ecu and when they dynoed it again the #'s were normal again. This was an isolated incident for them so I dont think its something that needs to be done consistantly. I think the way it works is it resamples information from the sensors and adjusts your curves accordingly, although only to a certain degree. I doubt that it will do anything for you by resetting the ecu. But it couldnt hurt to give it a shot.

 

An ECU reset should be done anytime you have altered any aspect of the engines intake, exhaust, and boost settings. This will head off most (not all) CEL's and it gives the ECU the chance to "learn" how the mods have affected the engine.