I would probably go with the 1.3 mk11 as i think it has the same tweeter and the same size mid/bass driver as the t2.5, this would probably give some form of synergy in regard to driver similarity. I have owned all of the Dyn contours from 1.1 to 1.3 SE to 3.0 to SPEC 25s, and the contour centre which is is similar to yours. The 1.1 is by the way what i am using (as a rear)and is an amazing small speaker, it is easy to enjoy because it seems less critical than the others but still has the same tweeter, the 1.3se's are fantastic and would probably trash the t2.5s in a musical context and with a rel (or similar) sub sound pretty awesome.
Dynaudio Contour 1.3 , 1.3mkII & 1.3se
I am building a five speaker h.t. system using Dynaudios. I've chosen the T2.5's as the mains and the T2.1 as the center, but I'm unsure what to use for the rears. I've heard the 1.3mkII's, but not the original 1.3's , nor the 1.3se's. I would like to know what others would think about using for rears. Please help.