I own a 2008 G6 GT with 108,000 miles, 3.5. Car runs fine but dont know if the orig. plugs have ever been changed ,and am concerned they may get corroded in the head. Ive read prev. post and it seems like Delco is the way to go, I,M guessing iridium. My plug wires say [wired for life] on them. Dont know if they are orig. or aftermarket. Want to put good plug wires on while doing the plugs.