Really Dubz.....got any dyno sheets on that? From everything I have seen, the step headers have been proven to be pretty much worthless. I have also never seen any information that supports the fact that large pipes will "kill" power. I have seen dyno sheets that do prove that a small amount of backpressure will produce favorable mid range torque advantages. When I say small, we are talking less than 5 percent. Of course mufflers on 3 inch pipes will usually provide a small amount of backpressure just because of the slowed flow.
So, I would like some supporting data(read dyno sheets) that large pipes will "KILL" low end torque. I did not say it would not be effected. Hot Rod magazine did a series of small block dyno pulls to test open, straight, H pipe, and cross over a little while back. They used 3 inch pipe on a fairly mild build, with good results. This or another also tested the step headers with no advantage over a header of the same size as the smallest tube. The theory is that the step size increases scavenging ability of the headers if I remember correctly. This would supposedly help in the top end of the power range, but the dyno did not support this.
I guess we should define "kill" here, huh.....