No torsion bars on these trucks. Cheapest option and what your probably looking for any front spacer kit, try Motofab, Rough Country etc. They are all pretty similar. Either a top or bottom spacer, some are a combination of both once you go above 2.5ish inches.
Next option is Bilstein 5100 leveling shocks.
Most expensive is Fox, King coilovers etc.
No mechanical difference for leveling, wheels etc 14 to 15 that I know of. Id just copy what you see there. As for tires those are MT(Mud Terrains) if you want less aggressive go to an AT(All Terrain). Most popular are BFG KO2, Toyo Open Country AT2 , and Nitto Terra Grappler.