Get the 178, with it being center mounted it will ski short and you will have more float in powder, if you go 171 it will be good for park but not as good elsewhere, don't worry about being 125lbs. they are soft skis so you won't have any problem also you might gain some weight.Wooah slow down. 178 is going to be HUGE if you're 5'8" I'm closer to 5'11" and I'm riding the 171's (anthems) and they are actually pretty long! You'd have trouble throwing around a 178 in the park. and for how they float, I honestly don't float all that well. But I'm way bigger than you, at 185 pounds and 5'11"... I just find myself leaning back so much to compensate for the massive tail behind me pushing me forward into the pow. Pretty much, you can't really ski pow ALL that well when your ski is mounted center unless you go with a rockered ski. The new ski everyone has their eyes on is the Moment Reno Rocker... I've heard good things about it, and I'll probably be getting a pair pretty soon, because a rocker is good for pretty much all aspects of skiing except for groomers. And this is the first park specific rockered ski. It makes switch ups and spinning on rails easier because you don't catch your tips. But as for the anthems, they are alright skis, not too heavy, not to bad in the park, their cheap, but there are better skis out there.