My opinion (which is worth what you payed for it) is that the Sonetta VIIIs are going to be a really big speaker for that room. I don't think you will gain anything by moving to the larger speaker in that small of a room.
I would look to step up to a higher quality speaker rather than just a larger speaker. Not sure what your total budget would be but that would be my first priority.
I would look to step up to a higher quality speaker rather than just a larger speaker. Not sure what your total budget would be but that would be my first priority.