This is going to be a write up on how to put an 96 4.0 in a Renix era MJ while keeping the Renix wiring harness and the Renix parts you can use and the HO parts that you can use. I also swapped in a 97 AX-15, so not all of these parts will necessarily be compatible with your transmission. I can update with part numbers for the parts that I ordered if it is desired
Renix intake manifold, that way no adapter would be needed to install the Renix TB.
HO header (it was just in better shape than my Renix header) (This is optional, your Renix header should bolt right up too)
HO exhaust (from the header to the cat), this will move your oxygen sensor into the exhaust instead of the header. Is there any benefit to this? I do not know. You will need to modify you intake a little bit to make these work together. (Not necessary if you use Renix header)
Renix CPS, this will make sure that you are getting the correct signal to the engine
Renix Flywheel/Flexplate, this will make sure that the CPS will get the correct reading from the flywheel, and allow it to start. An HO flywheel will not allow for the truck to start (ask me how I know)
Renix distributor, cap, and rotor, this is part of the Renix wiring system, so you need it
Renix spark plugs, again, goes with the distributor
All of your Renix accessories
Renix accessory mounts
And then just all of your Renix wiring (knock sensor, etc)