Ordering '08 F-350 Need some input

I ordered an '08 F-350, SRW crew cab, 8 ft box to replace a '03 Dually (DRW), crew cab, 8 ft box F-350. (Available for sale.) Need some input and thoughts on a couple items.

I tow a tag 26 ft. enclosed car trailer. The car inside is up to 4,000 lbs. The trailer tips the scale at 5K.

Questions:
Do I need a dually?
What rear gear should I order? Limited slip is a must.
Any other packages or items to help in the tow area?
Bump up tires and rims?
Should I try to position for Job 2?
Alternators has been covered on another post.

I have it pretty well loaded up. Just need to give the dealer any last minute changes on Monday.

Thank you in advance for your time and thoughts. This is a big move for me and I want to get it right. The '03 was purchased from a buddy used 18 months ago so I have no ordering experience.

The kid in the candy store is kicking into hyper drive. Jerry