Check out this site pictures:
http://www.honda-tech.com/zerothread?id=1199677

About the SMSP header picture. Is that header consider 4-2-1 or 4-1? Cause the design is 4-2-1 but usually the cylinder 1&4 become 1 and the other is cylinder 2&3 become 1. But in this picture is cylinder 1&2 and the other is 3&4. Can anyone explain? And what is the advantage by using very long pipe for the header? Thanks.

 

Longer piping tends to allow for a lower cam crossover point. The pipe paring has to do with R&D of the exhaust pulses, scavenging, better fitment, and a whole host of other reasons.

There is no one way to make a header. Dave as SMS makes some of the best products out there if you're looking for a custom header. If you want an off the shelf header, the TODA wins hands down.

 

So,if I make a custom header just pretty much the same specs as SMSP header and for the same engine will I get similar result (I know most probably not as good as SMSP)?

 

that is a pretty bad ass header