I have no idea how tall 180 is and I'm too laze to convert it, but I am 6'3" and I have XL pants and they are HUGE. They probably got about 8 to 10 inches past my feet when I have them on my waist and don't have boots on. I love them. You won't be unhappy with your purchase.
i have a full saga xl suit and i am 6'3 and about 175 and the jacket comes to about right below my hips/ upper thigh and the pants are very long (as if if they arent rolled up they cover my whole feet.) and i keep them roled up most the time i wear a 33X34 pant for reference.
I'm 5' 10" and the L fits me pretty perfect for a steezy/baggy fit. If you're 6' + then you might want to step it up to the XL (which is still pretty big on someone thats 6'). And if they don't fit you they way you want they have a good policy on returns, so that they get you the right gear!
Yeah, that'd be huge most likely... saga XL = Normal XL/XXXL. Like I said I like baggy clothes and i'm 5' 10", 175lb, the large fits pretty perfect. Unless you can fill in the XL's with a good bit of width i'd go Large.
5'10" at 15 isnt that ridiculous so I can't say whether or not you will grow a lot. For your height now I'd say go with large. But if you think you are gonna grow then it's up to you. You will look ridiculous right now if you get XL. I'm the same size as the guy above, about 175, and I can slip the pants on without undbuttoning them.
If you are 5'8" do NOT get XL pants. Jacket you might be able to get away with but pants no. No joke XL pants will but a foot and a half longer than your legs... and thats if you wear them at your waist.
Im 6' 3" and i like some baggy but not ridiculously baggy and i went with large, if your 5' 8" DO NOT GO WITH X LARGE unless you want ridiculously ridiculously baggy, this is how the large fits on me
Also, this is such a legit suit, when my friends are bitching about how cold they are on the windy lift up im perfectly warm even without a shiton of layers. Iv never gotten wet wearing it, iv bashed it against countless trees and its held up damn well with no tears.