1) I did succeed in getting a Superwinch 18k installed. But, it wasn’t as easy as I hoped
2) The holes drilled on a 10x4.5” spacing were a bit misaligned; I had to enlarge all of them and file one further out of round to make it fit the winch. My presumption is that the hole spacing was correct on the Superwinch, but imperfect on the Pierce platform. However, I admit to not measuring them – just making the adjustments necessary in the Pierce platform.
3) The Pierce platform did NOT have any 10x6.7” mounting holes and I was forced to drill them, as the Superwinch 18k uses 8 bolts to mount. I presumed these holes would be standard on a 20k platform. But it was not apparent or viewable on the website images or description.
4) Because the Superwinch is so large, I was forced to rotate the fairlead bolts; putting the thicker nuts and lockwashers to the outside. That is undesirable, as the clearance is so tight around the larger nut head that a typical socket won’t fit within the fairlead (either requiring a thin-walled socket, or “wedging” the nut head and tightening the bolt).
So all buyers be aware that it is a tight fit for a larger winch, the holes seemed to be imperfectly spaced on 10x4.5, and there are no holes drilled for 10x6.67" spacing. Otherwise, it seems pretty solidly constructed. I have not tested it yet under load.