I have an 08 XLV and I haven't noticed a squish sound in the basement of the boat but I've never compared the center compartment of the LSV/Outback to the XLV. I know for sure that the XLV center comparment has got to be much deeper that the other two models. However, I don't truly know if there is a false floor down there. As far as water getting into the bilge and/or under the void between the hull and gas tank...that's going to be from the in floor cooler on the XLV as it drains into that area in front of the gas tank and a small amount will come from the very little amount of water that will drip/leak from the ballast sac connectors in the center ballast. My boat storage area has a very steep incline that I pull my boat up (much steeper than the ramps) and I'll park there for a few minutes to allow that water from under the gas tank to make it's way to the "normal" bilge area and out the drain hole. So far, so good with me...I hope.