Consider that the new 160 may have upgrades the refurb 180 doesn't. The v4 of 4 years ago most likely is not the same as today's. The 160 also has buttholes on the rear. If it's too close to the wall, taming the bass could be a challenge. Finally, will you drive yourself crazy wondering what the behemoth sounds like compared to the 160?

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated