will it be a good fit? are the 1st and 2nd gen running gear parts swapable?

Considering first gen as SE series (89~98 in the US) and second gen as SQ series (99~05 in the US), I would say - no - it won't bolt up without a fair bit of work.

The SQ series has a wider chassis and quite a bit of difference in the under pinnings.

Last year at Moab, the guys that came with Mike Hagan were running newer tracker frames under their 1st gen Trackers.  One was running a 4 door frame under his.

Hiw much work did it take?

I do not know.  They were all running the newer frame with modification that Mike Hagan has on his ZR2 project.  Mike would know.

Hmmm does anyone have info on a gen 1 4dr body on a gen2 frame?

I have an 03 XL7 sitting, and I have been wondering about this same thing...being full body on frame shorting the XL7 frame wouldn’t be terribly difficult...I had done a bunch of measuring when I drug it home, and I think the newer frame is like 3-4” wider.

I have an 03 XL7 sitting, and I have been wondering about this same thing...being full body on frame shorting the XL7 frame wouldn’t be terribly difficult...I had done a bunch of measuring when I drug it home, and I think the newer frame is like 3-4” wider.

If your really good at welding on body mounts you could probably make it work. The location of the steering and brake setup might be an issue since your going to a smaller body.

Be one heck of a project.