Assuming a good fit into the room, perhaps some low end extension, but I would not expect much of a difference if integrated well into the right size room. If so, a sub or two could close the gap.
The OHM Walshes of a particular vintage (currently Micros and X000 series) are all designed to sound inherently the same in their target size rooms. Bigger drivers can deliver more output at lower frequencies obviously, but that's about it. The rest is the same just scaled up or down, which is quite a unique thing. You can get the best sound possible in a small room with micros or 100s, larger models add little or nothing.
My Walsh F5s and 100 series 3 speakers are both one series old. 5X models (the largest) come with 4 3 way adjustments on each speaker that provide flexibility in fitting those into any room, large or small. I have compared them to my 100s in my smaller room suitable for either and the sound is in fact essentially the same. The 5s are much bigger and are overkill though for a small room alone. They sit normally in my large L shaped room which is 20'X30' more or less. My smaller room(s) are both 12X12, each with very distinct acoustics.
