My wife considers to buy the K2 GotBack, but we are insure about the length. 160 or 167 cm? She is 5'5" and 90 lbs, 30 yrs old, a good skier since youth, but sometimes a bit anxious. So I thought the 167s would give her more security, maybe for the price of a bit less turning ability.
She tested the K2 PayBack skies in both lengths 160 and 167 cm and was not so happy with the 167s. But the PayBack has no Rocker and has 10mm less under the foot. Unfortunately we have no possibility to test the GotBack in Switzerland where we live.
What do you think? Would be glad for some comments, thanks.

IMO, If she is only 90 lbs then I would say go short, the 150-ish one (153?), or 160 if she loves to point the skis downhill or skis in powder all the time. I think 167 would be hard to handle with her weight even if she is an expert. I'm 1325 lbs/5'6" and I tried out the 167s. They were a LOT of ski. I'd prefer the 160s and I would still rip down the mountain.

Hard to say for sure, but I would suggest the 160cm. There is rocker on the nose of this ski, but it isn't very drastic. I don't think you need to size up with this kind of ski because of rocker like you would with a Hellbent or MissBehaved. The added width compared to the PayBack will give better stability, but may also make the 167 feel cumbersome and heavy. When I'm anxious on the mountain, I tend to make more and shorter turns. The 160 will help your wife with that style when needed. The GotBack's 102mm waist and solid wood core make it very stable at higher speed and deep snow, even in a 160 length. This is a very popular lady's ski here in Utah due to it's combination of float, stability, and nimbleness in all conditions.