What's the length of the primaries on the Knight headers? I have those Bursch headers with heat and they are 32-34" long primaries.
If the new Knight headers are shorter than 28" I suspect they may not do as well as the Bursch? We shall see.
But the Knight headers do have a favorable 2.25" exit on the collector, that could help if you have 2.25" pipe to the muffler
but the runner length is the most important.