To answer the question of the power ratings, the 160 has a single tweeter vs the dual tweeters of the 150/180. The single tweeter can't handle that much extra power. In our rooms the single tweeter is more than enough.
I did compare the 180 to my 160 and the differences are negligible. the 160 has better horizontal dispersion while the 180 hits a little deeper, provided a little more guttural feel to it, but really getting nitpicky with the depth differential.