2005 GTO SLP Headers, Coated 1-3/4" Long-Tube w/High-Flow Cats/Downpipes-shipping is not included Bolt these Long-Tube Headers on your 2005 GTO for a quick pick up of up to 15 horsepower and 17 foot pounds of torque. Your LS2 engine will really respond. SLP engineers developed these headers to maximize power through the entire rpm range with 1 3/4 inch primaries flowing into 3-inch collectors and downpipes, then into SLP's High-Flow Catalytic Converters (included). Use SLP's new Loud Mouth (#31560) or Loud Mouth II (#31561) cat-back exhaust with integrated PowerFlo-X crossover for the most power and best sound possible from an exhaust system. Headers come with ceramic coating inside and out to cut down on heat transfer, increase exhaust gas velocity, and reduce under-hood temperatures. All necessary hardware, gaskets and clamps are included for an easy installation. For off-road use only. NOTES: Not legal for sale or use in California on pollution-controlled motor vehicles. We recommend using O2 (oxygen) simulators to avoid the "Service Engine Soon" light which is not an indication of mechanical failure. GTO Long-Tube Headers Feature: * CNC mandrel-bent stainless steel. * Heavy-duty 3/8" one-piece flanges to resist warping. * Adds up to 15 additional rear-wheel horsepower. * Aluminum-ceramic coating for superior performance, appearance, and component life. * Easy bolt-on installation, no cutting or welding required. * Compatible with stock or SLP exhaust system. * Includes High-Flow Catalytic Converters, gaskets, clamps, oxygen-sensor extension harnesses, detailed instructions, and all required installation hardware.