They all have a D44 in the rear now.
The Willys only adds 3.73 gears, rear LSD, Rubicon wheels and tires, and the accessories bag/stickers.
I know you can get the gears on a sport, and I think you can get the LSD as well (might only be on the Sahara).
Personally I'd look into a sport with options and save some cash, or get the Rubicon.
Its also has the Rubicon rock rails and suspension. You can get most of the options on the Willys added to the Sport but I think the Willys package comes out slightly cheaper.