Champions are a crappy plug and always have been...I only put them in my lawn mower. NGK's are a very good plug and they also make the AC Delco plugs.

 

My experience working for Ford- I've seen lots of cars and trucks come in after the owner just changed the plugs with the car/truck running very poorly. Change the plugs to Motorcraft ones and it runs just fine. I've seen alot of Autolite plugs do this.

So my advice, stick with stock ones.

 

Changed to Autolite XP5263--Iridium with Platinum tipped ground pad--at around 35,000 miles. Like others have reported, the stock Champions didn't look too bad--gap was at .050 vs. factory recommendation of .045 and the electrodes were slightly rounded. I was having no problems, but replaced them anyway per severe service recommendation. Used anti-seize. After 4,000 miles, no change in anything after the switch. Same MPG, same idle, same highway operation, no problems whatsoever. I hope to keep these plugs for at least 60k mi since they are such a pain to replace.