Binarypie, I agree with you completely about the size--and that is why I will keep my Ride SPI's on my Billy Goat for really deep days when I just want to go fast and big. I have ridden that board for years in the trees as my only powder board, and I love how powerful it feels, but after weeks of riding a 156 Omatic Awesome (traditional camber) in the park waiting for a storm to hit it becomes apparent how much the 162 Billy Goat just likes to go forward and fast.
Do you really think the 158 won't be that much easier to whip around in the trees? Honestly that is something I am really hoping for, in addition to being able to ride switch in powder more easily and throw in a quick spin or log ride here and there.
As for my comment about the channel...I think what really makes me apprehensive is I have broken bindings by whacking them on rocks buried in powder and I wonder just how much abuse two screws and the channel can take... If it makes any difference I would be using adapter discs and not actual EST bindings. I'm guessing you don't have any complaints about the channel though Supra?