With the mods ive have done yes I am able to tell a difference in power. Its not a huge difference but the truck does feel more responsive. If I had to decide between the MP PCM and headers I would definitely go with the PCM. My first performance part was the MP PCM and you can feel a small difference with everything else stock, but every time I add a new performance part I can feel more and more of a difference. And if you are wanting to upgrade your y pipe the best thing to do would be to go to your local shop and have them make you a 2.5 inch y pipe or do the true dual setup.