I looked at doing a diesel in mine and this is what I came up with. Drove a 4bt in a jeep. I would not have done that conversion because of the vibration and noise. Looked into the 6BT. About a half a year later killed that idea due to what it will take to convert it and watching all the issues people had with the conversions. This was not only in cruisers but I researched everything I could. next I wanted to do the factory diesel. Almost bolts right in, I don't have to worry about someones adapter, trans mod, tuning mods. Then I tried to look up parts for it. If I broke down, I'm importing. Cant grab from local part store. They were never offered in US.
Bottom line was, with me doing all the work, rebuilding the motor and trans, all the misc things, I was looking at 10-20 grand depending on which way I went.
Beside all that, you and I both have a 96. That means OBD2. Translated means it has to be inspected. Even the diesel will have to meet the requirements and the non us motor will not. 1995 and your clear. When I did this research I hadn't bought mine and was looking at the 95's just for this reason. The Cummings 2.8(?) is 50 state legal and is a stand alone system.
The last challenge you will have is this. You need to be the expert and do all your own diagnosing when something fails down the road. I have done or helped friends on over a dozen engine conversions over the years. All of them met CA smog laws. Being a tech for my whole life has taught me one thing. If I have an issue with diagnosing, I look into the factory manual for specs and procedures. On a conversion, one doesn't exist.
The last one I did was a 2004 4.3 GM V6 and 4L60E trans into an 84 Toyota PU. Rebuilt the engine, trans, fabbed a bunch of stuff and it came to almost 9 grand when done (no labor). This thing was perfect. 3 years later, I get a call and it wont pass smog. He took it to several shops, they popped the hood and made him leave. He had put the wrong plugs in it was all.
As a tech, how much time (money) are they willing to invest diagnosing something that they have no spec or diagnostic procedure for. If you are good enough to be able to do it yourself, I would suggest the Cummings because of the registration issues with the other's. I think its 8 grand? I was looking at 8-10 for an aussy motor by itself.
Good Luck with what your doing. I just ate a head gasket and am rebuilding the motor. Had to tear my eyes away from an LS2 swap....
Scott