The 18" tires and special aluminum wheels are part of the King Ranch pkg, and the towing pkg is standard on all Super Duty pickups. But you have to order the optional 3.73 limited slip rear axle.
If you haven't already done it, download the 2008 F-350 Order Guide from
Sunrise Ford Fleet, 16005 Valley Blvd, Fontana, Ca, 92335 . Become familiar with what options you might want that are not included as part Lariat trim and King Ranch pkg. Then as soon as Bobby posts the 2009 Order Guide you can download that and already be familiar with the layout. You should be able to see what changed for the 2009 models and spec out your 2009 model.
For example, air conditioning is an option in the order guide, but you don't order it because it's part of the Lariat trim pkg, and the Lariat trim pkg is required to order the King Ranch pkg.