You have a GT, so you did good by getting the iridium plugs. If you were blown or boosted, you'd want to go with a cold plug, but you're not so you don't. I would have bought Delco/Delphi wires, but it's your money and thus your decision.

Be aware that the flashing code MIGHT be a bad coil pack. That happened on my Camaro and had me chasing faults all OVER that freakin car.