I'm now due for the first plug change on my 05 Magnum HEMI.
Local parts stores all told me the plugs were "dealer only."
Dealer wanted $4.99 plus sales tax of 8.5% for 16 plugs = about $86.60. I was able to find some web sites which sell the right Champions for about half that price, plus shipping = about $54.
Bottom line -- don't buy plugs from the dealer, and don't believe the parts dummies who tell you the parts are "dealer only." What they really mean is that they don't stock them.
Dan