ARH - Long Tube Headers & X-Pipe (04-06 Pontiac GTO)ARH GTO systems are here to make a statement. Manufactured in 304 S S, these headers are available with 1 3 4" or 1 7 8" primaries. Merge collectors with scavenger spikes are standard along with our bullet proof high flow metallic substrate cats. Systems are available as a direct built in for all 2004 2006 models or choose our 3" X Pipe option. Expect outstanding performance gains throughout the RPM range and a fit and finish second to none .