When I converted my last trailer to oil bath I called EZ Loader and I needed to get new brake drums in addition to the conversion kit which added a couple hundred bucks. So depending on your trailer the cost might be higher. The EZ loader system is NOT a “Liqua-Lube” system. “Liqua-Lube” uses their own proprietary synthetic oil. The EZ Loaders use a 50wt or ? gear oil I think. Someone correct me if I’m wrong.
And for what it’s worth, Shorelander says if your trailer sits a lot, they recommend you spin the wheels every couple of weeks to keep the oil on the bearings because moisture can get in there through condensation and this could cause pitting of exposed bearings. I usually use my boat every weekend (when I have one

) so it’s not an issue for me. I will still use oil bath (Liqua-Lube) but there is still maintenance to be done.