I just wanted to let the 04 Grand Prix owners know tha with the redesigned SLP headers for the 2004-2005, the fit is perfect with only two minor mods. First, you need to bend down the upper AC line going to the AC Compressor about 2 inches. And second, the metal backer plate on the passenger side fan needs to be removed. With both of these done, there appears to be no contact issues with the headers and the car.
Robert
Robert