Define better. Better performances; yes, but the overall comfort and unreliability makes the aftermarket headers not worth it to many people. But the faulty sensors + lesser quality fuel is really looking for trouble.
But for somebody that doesnt mind having a christmas tree in the cluster; i'm sure its a good decision; performance wise. Even the O2sims seams to give SES on a random schedule. People that bought SS or OBX headers had the same issue with the SES.