It depends on what you want. A stock e6 is fine but if your goal is 300 plus then you will need to step up to the plate and buy a header. I doubt anyone has one in stock except for ATR (because no one wants their crap). I am sure there are a few at the reunion this weekend for sale.
I vote for rods header (Had one for abiut a year now) but stingers is nice too ( I havent run his)
I have been looking at Rod's header and it looks like the way I'm going to go. Looks like a nice part. and it's priced pretty well, 505.00 for the config I want. . .