we talked about this one before
The +4 platinum plugs are a rip off... they are no better than regular Bosch platinums (which I use in my Trep). The +4 plugs are only good for cold starts. That is it. They spark once, just like EVERY OTHER spark plug, and they don't provide any better fuel economy either.
Save your cash. Oh, and the only reason Champions are pushed so much is because MOPAR claims that they are the only 'authorized' spark plug. yeah, right.