I say the 159 for sure. Im 6'0 185 and I got the 156 Custom V. However, I ride Socal, park and jibs, with the occasional powder day. The 156 is def small for me, but its good the the area Im at. If I was at a bigger mtn or had more pow days, Id def be on the 159.
Btw, I agree with everyone else here that the 'downsizing' is a joke!