there are threads on here for plugs that members have used and are happy with, i have the 3.7 with Bosch plugs. found better performance and fuel. Go to the dealer and they will tell you that these plugs are not 'recommended'.
Model: Nitro SXT 3.7L
Build date: Jan 07
Mods: Projector Head Lamps, Bosch Platinum Plus spark plugs, Hella projector fog lamps with Landy chrome bezels. Custom undergrille.