When you install a 2.5" lift kit, you'll need longer shocks.
There's three ways to do this: (1) Buy a kit that comes with longer shocks, (2) buy a kit that doesn't come with shocks and supplement it with good shocks of an appropriate length from another company, or (3) buy a kit that comes with shock extensions to extend your stock shocks.
So now do you see why the TeraFlex kit is offered with three variations? You can get any version you want, but you'll need to account for your shocks somehow.
As to wheel offset, Discount Tire is a sponsor on this forum. Send them a PM and you'll usually get a good price and the right information.