I've got a bilge on my x4, it's mounted behind the flywheel in front of one of the bailers. The PO put it in near the battery, but he only JB welded it and it came off. I thought that was a bad place for it, as the water likes to go to the back of the ski, so that's where I installed mine. I drilled a few stainless scres into the fiberglass (after making a very small pilot hole) and put jb weld around the hole when installing the screws. I screwed down the bottom portion of the bilge pump (the plastic strainer cage that clips on/off the actual pump). It seems to hold the pump on rather well even with my 10ft jumps and occasional rolls. I have a water-proof switch routed to the front (another driled hole). I used to have a regular switch, but when wet, it shorts out and the pump runs. You won't even know it's running until you cut off the ski and hear the noise. It came in handy when my exhaust pipe bolt came loose and I was taking on cooling water. I plan on retrofitting all my doo's with bilge pumps eventually, they're good to have and relatively inexpensive. The only thing I hate about mine is where the PO installed the outlet: right in the middle of the back of the hull, ugly and obvious as day. While not looking at the ski, I"m not sure where would be a better place for it, but there has to be one.