Generally ECUs are set to a 'safe' setting. The manufacturers dont know what the conditions the cars will be in (altitude, fuel quality etc) so they might run them a little richer/leaner etc to prevent knocking/poor performance. Also each engine/car combination will have its own little quirks, which they don't account for in the factory tune.
So when you get them dyno'd and tuned, the tune is tailored specifically for your car and environment, allowing for a boost in power.
So when you get them dyno'd and tuned, the tune is tailored specifically for your car and environment, allowing for a boost in power.
