My 5er came with this sliding tray option and it is something that now I would not be without. Ours slides out the same amount on both sides which makes it very simple to load and unload any stored item.
Our basement also has space under the sliding tray approx. 8 inches deep which is handy for storing items that are not so frequently used. I built an area in the dead centre of the sliding tray and carry my Honda 2000 generator in there.
The sliding tray when purchasing a unitmay seem like too expensive an item, Definitely It Is Not.
2008 Topaz F254SS 26 ft.
2009 Chevy Silverado, 2500HD, Duramax, Allison Tranny, 4x4, EC
250 watt solar panel system, BlueSky controller and remote