How much lift can I go with on a 93 splash 3.0 before I have to start replacing other parts or modifying

 

I don't know !
What I think will happen is the Body to Frame gap will get so large you will be able to store things under the truck but have no more ground clearance than a stock Ranger. you have to worry about thing s like brake lines in the engine Bay Area, the gag lines, the gas filler tube, Clutch lines to the slave, if you haven, stirring connections, over two inches working on the engine starts to get more of an exercise in contorsionism.
Also, heater hoses, and Radiator hoses.
IMHO... I would do no more than 2" of body lift, that alone take a lot of small parts, and buy a good kit and you will receive all lot of the added parts to lift the cab and bed off the frame the way t would be.

It is not as easy as you might thing.

 

Yes +1 ^^^^^

And bumpers are attached to the frame so 2" lift = 2" gap from bumper to body, 4" lift = 4" gap

And steering column needs changes as well