i had 05 ar5s they were sick now i have 06 stls they are sicker. they are the ar5s except a bit stiffer a wee bit wider more stable switch and the swingweight is the main diff, muchhhh lower. Ar5s are super sick though.if it only those two skis id say ar5s cause the 183 stl will be too stiff for you. im 6'4 180 lbs and its perfect for me id say get one size smaller stls or 176 ar5s or 180 ar5s work too.
I love my STLs... they broke in sooo nice. Im looking for some Armada's right now, but yeah i love my STLs... prolly the most fun ski Ive ever riden. From the first day I was like god damn these are fun, and super poppy for being soft.