It is very easy. On my '99 it only took about 20 minutes. I used the Westach electric gauge. I put a grease gun hose on the sender & installed this on the post filter check port on the filter housing. This is the one near the center. Then I just wired it up & checked for leaks. Don't use any teflon sealer tape, I believe diesel disolves this stuff from what I've read.
Gotta warn you though, I am not thrilled by my Westach gauges. I like the way they look but the electric sending units are erratic. Sometimes mine works & sometimes it doesn't. I also installed a cheap NAPA mechanical gauge under the hood to make sure everything is fine.
Good luck, this is a very easy job.