What's really awesome is how much $ your ingenuity saves.
Check these out...
http://www.burnsstainless.com/MergeC...ollectors.html
Click on the 4-into-1 and the Turbo Collectors buttons at the top of the page. Buying a pre-fabbed piece (that still requires further fabrication) that's built to the highest standards of materials and design starts at around $350. Add mandrel-bent piping and a flange and you suddenly have the most expensive header money can buy.
I've always wished I could win a 10-minute shopping spree on that website. Building my own charge pipes using the stuff they sell would cost me around $2200... and I'm a cheap-ass DSMer, so that will never happen. :P
Like I said, looks great! I can't do better! U gotz skillz.