I have read that if you change one or the other, (intake or exhaust) you don't need a tuner/programmer. I have changed my pipes and don't have a tuner. All is fine. Same goes for modified stock pipes.
The tuner is to adjust the fuel mixture - lean or rich - more or less oxygen. A hi flow exhaust and intake will need to have the air/fuel mixture adjusted. That is my laymens understanding of it. Hopefully someone can add to it. I am no mechanic.