I have an 02 gtp coupe, basic mods n bolt ons. Cai cone, upgraded pcm, bolt on downpipe, slp exhaust, headers, msd ign coilovers, ram air hood, my SES soon light is on with the dreaded po420. Tested and double checked and the catalytic coverter is fried. It was stock, so I assume that I shouldnt go with another one. There are many universal cats by magnaflow and flowmaster but does anyone have a good opinion on which one to go with or what to do? Ive seen dummy plugs but dont know 100% how those work either. Any advice helps! Thanks!
