A a result of new exit options, the A321 now officially has a max seat count of 236 seats, the A320 of 180 seats.
A difference of no less then 56 seats between the A320 and A321.
edit:
Coincidently Ryanair CEO today confirms the A320 series seat gab compared to Boeings -800 and -900..
As for Ryanair's decision to place that new order from U.S.-based Boeing instead of Airbus of Europe, O'Leary said, "Look at the economics of the 737, the 800 [series] has 189 seats. The [Airbus] A320 has 180 seats. And those nine extra seats when you're flying them eight times a day, 365 days a year are a compelling competitive advantage for Boeing."
Ryanair CEO Calls Boeing 787 Problems 'Regulatory Crap'
And 180 seats for the A320 is truly pushing it. Few operators dare..