How hard was it to remove?
The unit wasn't too bad. 4 bolts hold the unit on. They were a little hard to turn. Either corrosion or perhaps a thread locker used to ensure they don't back out.
There are two water lines for cooling, the fuel inlet, two high pressure lines and one other line which I assume is low pressure fuel or perhaps another water line.
The high pressure lines came free fine. One was still under pressure so it made a bit of a mess when I got the tube to come free. That was a bummer as I don't like fuel spills and the associated smell. No fire risk as there are no spark sources there.
One of the water lines comes off easy. The fuel inlet is always a bit of a bear. I've contemplated switching it to an AN fitting as I have to remove it every year to winterize. The one coming out of the top of the filter was the most challenging. I could get it to spin, but couldn't get it to come off. Almost to the point of cutting it I got a pick underneath it and was able to get it off.
Overall, not too bad. Today, I'll work on the fuel filter itself. Plan is to screw it to a board and mount it in the vice and see what I can do.