To my knowledge and in my experience, Sonus Faber speakers actually work better with higher ceilings, but probably not with 18ft ceilings in mind (wow that's high). I think it comes down to speaker positioning and how far you're willing to go to make it work. If you're going to have the speakers placed close to the walls and your listening position way out in the back, I would say no it wouldn't work so well.
I think it'll work better if you treat the room as if it's a much smaller room. Obviously you have to set up the speakers properly. But I think you might want to set it up using more common distances such as having them 8-9ft apart, 3-6ft from the side walls (not equal of course). But more importantly, you probably want to have the listening position much closer, near the center of the room rather than 1/3 into the room from the back. Even with other speakers, you might be better off dividing up the space in your room rather than utilizing the entire space. I'll let others with more direct experience to comment.