i think it depends on what type of riding you're looking to do. i know you said all-mountain, but are you charging the steeps looking for lots of speed? maybe popping in to the trees every once in a while? or just cruising and enjoying life?
I'd recommend the 167 if you're charging hard, enjoy lots of speed and maybe like being a little scared. for anything else go with the 163...it will be lighter, more comfortable, and more maneuverable then the 168 that you're used to.