Definitely demo the AC30's in 170 and if you are even thinking of 177, demo that too. 170 is probably right for you. This might be unpopular, but in my short time on this unbelievable forum, the folks outside of New England have a tendency to recommend longer. The AC30's due to the 2 sheets of titanium ski long. I am 5'6" 145 and ski them 163. While I agree 163 is short for you, I would tread carefully considering 177's. Also, think about the turns you like to make, the longer the ski the larger the radius turns. While I have a blast bombing down wide open trails at high speeds, this is New England and many of our less crowded more difficult trails can be steep narrow old school trails. These are not even 17M wide. Obviously, you can turn a ski shorter than its radius, but I assume that is easier on western snow than our eastern hardpack (frozen granular or ICE!). just my 1 cent. The markets took the other cent.