The PT Cruiser started life in 01 with a conventional factory installed Champion plug. The new line of mini-vans with the 3.8 get a factory installed double platinum, (7440). Late in 01 the double platinum 7440 was added for customer replacement in the Cruiser. Champion has now added a new plug the 7570, and now recommends it for the Cruiser. It is identical except for the addition of a fine wire electrode. Champion still lists the 7440 for the 3.8 mini-van. I would think that the fine wire version would be better for this application as well. Champion claims that it needs less voltage to generate a spark.
The latest addition is plug options from Champion for these applications is the Iridium double platinum plug, the 9403. It is a fine wire design with platinum at the ground electrode and iridium at the center electrode, but with a shorter nose reach than the other two.
Upon removal of my two sets of 7440's (dual plats), I found that the 7440 plug lasted longer in my mini-van than in my Cruiser. At 42,000 miles in the mini-van they still looked perfect and measured well within spec. In less mileage the Cruiser set was showing significant wear on the ground electrode. I have switched to the 7570 (as recommended by Champion) for my Cruiser and have switched to the 9403 for my mini-van.
Richard.