Sport Compact car magazine did a huge test of all different brand headers a couple of years ago on an integra. Did systematical runs with same temp and stuff. The DC sports header boasted the most horsepower gains over all the others. something like 7 at the wheels(not positive). This is all from memory but DC sports is what I got and is a good hunk of metal.

4-2-1 has better mid-high gains
4-1 has better top end gains

I have the 4-2-1 and I like it!