I have a pair of Rel T/5x's paired with my Dynaudio Special 40's.
I put them next to the speaker stands where I had planned when I got them and after trying to dial them in did not like the sound. I then put them in the front corners, back corners, and eventually out into the room on either side of the couch behind my listening spot. Even a few inches off the precise location I set based on listening tests messes with the sound.
I have a nearly square room that may make placement a particularly big deal for me.