Is it stock? If it is and you want to lift it, I suggest the Old Man Emu kit, you can get that from Cruiser Outfitters. I've also heard that the rear part of the frame is weak if you plan to tow or carry anything in the rear hitch so you can get frame plates that you weld on to strengthen it. Depending on your intended use, you may want to add some type of slider. Other than that, run it. They are awesome trucks, I love my 03 and wouldn't trade it for anything.
Another popular upgrade for them is bumpers. I like the Shrockworks bumper but I bet the ARB is the most popular.