How hard it is to swap to a 2.6 becomes a function of several factors.

1) How much mechanical experience do you have and how willing are you to tackle a complicated project?

2) Regardless of experience, do you currently have the tools/location to do such work? This is not something that should be done in the apartment parking lot.

3) Do you need this vehicle every day? This is not something you will be able to do in a weekend and get you to work on Monday..

4) How much are you willing to spend? If you swap to a 2.6, your major cost is going to be the engine. Plus that, there will be a good bit of time making sure it fits. I don't think so, but you may have to move engine mounts (requires some welding).

Is your time, plus the cost of parts worth it to you? You will be reaching an amount where you could just buy a trooper from a better era(88-91), with a FI 2.6 and no custom engine swap in it and be better off.

Just some things to consider.

Good Luck,
Michael