Interesting topic. I use the thin Fluid Motion liners, that look a lot like the Radar Vapor ones (but thinner), in a Reflex. They work well for me on fit, as I'm lucky that the contours of the shell match my foot and I have no room for a thicker liner. But, what do people think of thicker liners? Greater comfort, I'm guessing, but any loss of feel or control? Better to have a slightly looser shell, with a thicker liner? Do thicker ones add any stiffness? I've used the snow ski racer's principle of anything that separates you from the ski being bad, but see some preferences for thicker. Are orthotics a good way to go? I always had them in my jump bindings but never used them for slalom or tricks.