this.
unless you are a complete park rat, i'd go with the longer ski. Im 5'8 165 and bought a pair of k2 seths at 179 and in retrospect really wish i got the 189's, longer skis add alot of stability and if your hittin drops and shit the extra tail helps, and in all honestly if you are a solid skier, 10 cm's more isn't going to make the ski that much harder, and after like 2 runs you'll be used to it.