What size snowboard should i get.?

Personally I would go with the 163 because the longer the board the faster you go. I am 6' and weigh about 130. I ride a 162. I don't think that you will really notice a difference either way. It also depends on if you are a park rider or a free rider. For park the 159 would be better. For riding the 163 would be better, but at the end of the day its your decision.