Looks like Carpenter is close to producing a different header for our beloved Rockets. They say it is a "3 into 2 into 2 into 1 header" and named it the "TXL". Doesn't look too bad if ceramic coated and equipped with heat shields. Not too promising for the GT model though.
I have rode and heard the CarpentEr bikes and they are very loud. They are hot also having no heat shields. It takes more than a pipe to make a Carpenter drag bike. That pipes would be so open that it would most likely need a tune to make it run correctly.