i have the DP mufflers too, stock header. I’m debating getting a header, but that said, the crossover and mufflers give it a nice sound and not stupid loud. I cannot speak to power because I did the muffler, crossover and ramair at the same time. Add in the hanso tune and I noticed a definite difference in power. Haven’t had it on the dyno yet, but that’s the plan for this season.