Currently (January of 2012) Dodge ships Pennzoil to its dealers, so that is most likely what the use at the factory. Over the years they have also used Mobil among others.
The oil you by over the counter at a Dodge/Jeep dealer is currently made by Pennzoil, so that is the best guess as what they use at the factory.
5W30 is factory recommended
5w20
I use 15w40
A 2014 Dodge Charger will use 5W20 oil. This oil can be purchased at any auto parts store.
10w30
Use 10w30 in a 1995 Dodge Dakota.
5w30
Yes
It shouldn't use any between oil changes.
Factory plug is 13mm.
Factory recommends 5w-30 grade oil.