I have a beautiful, rare 1973 GTO with one repaint of the original color, perfect interior and a NOM 400 with a mild cam.. Yes, rare. everywhere I go nobody has ever seen one before! About 4000 were made. Is there any reason I shouldn't put headers on this car? I like stock but the 73s were seriously down on power. Is one brand better than another? How about Hooker? Headman? Dougs (OPG)?