Originally Posted by SouthArk370Z

The rule of thumb seems to be: If you make only exhaust mods, a retune is not needed (the ECM will compensate). If you make only intake mods, a retune is not needed. If you change the exhaust and intake, you probably need a tune (outside the range of what ECM can adjust for). But that's just a rule of thumb - mults did both without tuning and doesn't seem to be having any problems.

It would still be a good idea to not go WOT until you've done a few less-than-full-power runs while monitoring knock, vibration, AFR, &c. Feces occurs.