heres the wording:

Stainless Works introduces its new Muscleflow performance headers for 2003-2005 4.8, 5.3L Chevy/GMC Trucks. Manufactured from 304 Stainless, the headers feature 3/8” thick, CNC laser cut flanges, and CNC mandrel bent 1 ¾” primary tubes. The headers are completely tig welded together, and are designed with a slip joint collector that uses 2 ½” headpipes and high flow catalytic converters for OEM reliability. Stainless Works long tube design makes excellent low end torque and mid range power while maximizing ground clearance. Stainless Works Muscleflow headers are the only ones available with a limited lifetime warranty, so they are guaranteed to last as long as your truck. MSRP start at $699.

 

some pics from gmhtp:

 

 

couple of things I really like about the stainless works headers is that they are stainless steel, fully tig welded, and they don't have that one primary that humps over the top like the Dynatechs

 

they say 2003-05... will they work for 01's tho?

 

not sure on that, I'd call

 

Why didnt stainless go with a 3" collector?? Thats a big plus on the Pacesetters IMO. On the Dynatechs. I couldnt find a metric conversion from "thick wall" to any unit of measure. So I cant compare the thickness to any other header. Who knows how thick "thick wall" is?

 

All their(stainless works) headers are made to order

 

Those look pretty nice moregrip...(I think that the Dynatech hump is kinda funky too) Too bad I don't see any info on em for a 99 w/ EGR. Actually, the EGR deal might have something to do with why they don't list them for the earlier model NBS's.

 

Kool. Buy me a set when you get yours.