If you can't rebuild an engine, you probably shouldn't attempt to regear your Jeep. Only you know your mechanical ability. If you regear with 4.56 gears and run 33" tires you should keep your power (I run this setup). It costs about $1200- $1600 to regear both axles (parts and labor). If you have a Dana 35 in the rear it might be cost effective to just buy a new rear axle with a locker and gears already setup in it and only get the front axle regeared (I went this route). Good luck.
2013 Wrangler 2D, 3.6L, Automatic, 3.73 Gears, Limited slip in the rear, Teraflex 2" lift, 285/75/16 tires.
People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf- George Orwell