To match the capability of a Jeep Rubicon Wrangler, you will need a low range t-case and lockers front & rear. Otherwise you can't compete. While tires & lift may not be big expenses, regearing & locking is. Gears, rebuild kits and labor will likely run you $400 an axle, plus $600 per axle if you decide to add lockers. And that's likely a non-selectable locker. Plan on $900 per axle if you go with an ARB or Ox. Plus you need to get a better t-case in there to even consider playing on the rocks. The Samurai comes with a 2.2:1 t-case, the Rubicon has a 4:1.
Just the other day I saw a used 2003 Rubicon for $8k. To get a Samurai to that level, you'll need to spend $2400 on gears and lockers for both axles, and $600 on a t-case gear reduction kit. That doesn't even include labor, and rebuilding a t-case isn't that cheap. Once you factor in the "upgrades", I wouldn't consider that Jeep a poor value at all.