JDM engine for first gen X.

I have a 2000 x vg33E (the engine in the picture) manual 4x4 with 158k miles. I want to keep mine forever and I know eventually with enough miles I will need to drop an engine in it. When that time comes. I was thinking of putting an imported JDM engine in it. My main question is are all 00-04 engines the same? I know there are a few mechanical differences between first gen’s and 1.5 but they seem to be minor. For example my x calls for 15 degrees initial timing and later years call for 10. I know that the ps lines on my 2000 are specific to that year. I have seen many parts as I have fixed mine up that are labeled 01-04. Has anyone put a 03/04 engine in a 2000 or vise versa. I have also heard that the pathfinder engines are supposedly different than the xterra engines. Does anyone know of any mechanical differences in these first 4 years? Im mainly making this post to expand my knowledge of these cars and see if we all can compile as many mechanical differences within the WD22 generation as possible. Cheers to expanding the knowledge of the xterra community.

I have a 2000 x vg33E (the engine in the picture) manual 4x4 with 158k miles. I want to keep mine forever and I know eventually with enough miles I will need to drop an engine in it. When that time comes. I was thinking of putting an imported JDM engine in it. My main question is are all 00-04 engines the same? I know there are a few mechanical differences between first gen’s and 1.5 but they seem to be minor. For example my x calls for 15 degrees initial timing and later years call for 10. I know that the ps lines on my 2000 are specific to that year. I have seen many parts as I have fixed mine up that are labeled 01-04. Has anyone put a 03/04 engine in a 2000 or vise versa. I have also heard that the pathfinder engines are supposedly different than the xterra engines. Does anyone know of any mechanical differences in these first 4 years? Im mainly making this post to expand my knowledge of these cars and see if we all can compile as many mechanical differences within the WD22 generation as possible. Cheers to expanding the knowledge of the xterra community.