Will bass overload room?

You won't have any problems. I had the 8's in a room about the same size.

I currently have a pair in my dining room, which is similar in size too your room, but with a higher ceiling. Excess bass is definitely not an issue. I actually find the speaker a touch lean in overall balance in that room which, I should note, has a lot of wood and glass surfaces that can't be treated due to WAF issues.

You can't state anything with certainty until you've actually heard the system in situ, but I'd think the risk here is low.

Marty