Would running a 8000lbs winch, 5, 130watt lights, 2 55watt lights and onboard air require a dual battery set up or changing the alternator or battery or both?

 

That's enough for me, in your case to consider all of the above available to raise your power and make sure all those accessories work. Even all at the same time, you never know.

Might want to upgrade cables and the whole nine as well, while you are at it.

 

go with dual battery setup, you're bound to add more stuff so may as well be ready for it

Echo - what setup is that - where did you get it?

 

so, just 2 batteries... I could leave the stock alt. alone?