The 4* is a great ski. I purchased a pair in the middle of last season. I had a chance to demo the 5* twice last year but cold not find a pair in a 168 to purchase so I purchased a pair of the 4*’s. I have the non-motion version with a piston 1400 mounted on them. I think the motion system dampens out the ski too much. I have a pair of Volkl carver motions in a 177 and never really liked them. They just weren’t snappy enough for me. For eastern skiing, I would consider this an all mountain ski. I skied these twice in over 6 inches of powder last year and they were fine with that 112mm tip. If you are looking to improve your carving skills, this ski is perfect. This ski wants to be up on edge all of the time. It handles bumps well too. What I really like about this ski, is you can crank out quick turns even at slow speeds. I like to ski fast and these skis are not bad at high speeds. I think that’s where the 5* takes over and the reason why I’m still interested in purchasing a pair. For size, both would be fine. It goes back to the type of turns you favor. Obviously the 158 will give you a smaller turning radius. I’m 6’0 and ski the 168. If you are skiing now on 177’s, I think a 168 would be fine. I’m considering selling mine as I just purchased a pair of Atomic SL9’s in a 160 and Head im75 chips and I’m still thinking a t50 5* in a 168 or 175. So, with all of that being said and if you are interested in purchasing a used pair in great shape, PM me. I work in Framingham.