Which Adire sub? I'm guessing you're talking about the Brahma? The 10's are a bit more responsive, and the 12's drop a bit lower and offer more SPL. Both are very nice, either will suit you well. What kind of music do you listen to and what are you going for?
Not necessarily. 10's are more responsive, better for rock, jazz, any music that has faster, more responsive bass. The bigger subs are more suited to boomy music and those trying to achieve SPL.