A TJ with a 2.5L and 4.10's will do what you need it to do offroad. You may have difficulty maintaining highway speed with it on-road (especially if you increase the tire size).
I've actually seen a bone-stock TJ with a 2.5L make it through that same crack...but going uphill. You would be shocked at the places that a stock TJ can go. That said, it took fifteen minutes of repeated trying and failing for that stock TJ to make it through, a VERY good (and patient) spotter was required to guide the inexperienced driver through the obstacle, and it required the Jeep to be pushed harder than I would comfortable pushing my Jeep...but my trail rig is also my DD.
If you've got recovery points front and rear and a set of mud terrain (or even all terrain) tires in good condition, then your Jeep has everything that you actually need. Add a CB, a fire extinguisher, a shovel, an axe, and some basic recovery gear (gloves, snatch strap, and a 3/4" shackle) and you'll meet the requirements for 75% of all CJA runs. Add a winch, and you'll meet the requirements for 90% of all CJA runs.
A stock Jeep with open diffs and a 2.5L will still take you a lot of places, and it will teach you a lot of things about wheeling. Like vantages said, it's all about driver skill. Choosing the line, knowing where you're placing your wheels, and understanding exaclyt how much "bump" is required is 80% of what wheeling is about.
P.S.: The first Jeep going through that crack (me) didn't have the lockers engaged at that point. On the way uphill through the crack that day, I has only the rear locker engaged...so that I could try a different and more challenging line. A week later with snow and mud all over the crack, I needed both lockers. Lockers do make a a difference when the going gets tough...but they still don't count for as much as driver skill and experience. I know guys that can drive open/open through things that I find challenging even with lockers engaged.