id recomend just getting ur OEM plugs ,
i had the NGKs in my maro , fan fine, always had a slight rough idle

added headers to my car and it was a whole diff story , ended up going back to OEM plugs and it runs very smooth


1997 30th Anniversary SS,Jethotts/ORY/GMMG, 160thermo, ,TB bypass, 1LE intake elbow, BMR STB, 32mmswaybar..21mm rear,BMR LCAs, PR,SFCs,TA,LT4 KM,255lph, shift kit