Tuned length headers
From what I've read tuned length headers create more of a vacuum in the exhuast and pull the fumes out better than non tuned length headers. This effect is called scavenging. So headers like QTP SLP and Flowtech should make more power than Pacesetters or Hedman.
I think what you mean is equal length headers and it dont make a difference from what I've seen on these cars. I think what you should be more worried about is the merge collector and weather or not there stainless. Go with the QTP's and call it a day. If you search in the dyno thread what the bolt on cars are making with SLP or Hooker or pacesetter you will see that they are pretty damn close but QTP's make a couple more ponys then the other guys. Check my sig.
