I think it's a matter of a lot of factors JPA. One is the designer. I recall reading that the variations from designer to designer could be as great or greater than the differences between the actual parts (like DNA360 to 205)
So something like a FUSION 12 + FUSION 8 Rears + FUSION 8 MTM CENTER work really well together (all done by Jeff Bagby with like style crossover work).
In general the timber differences isn't a huge concern IMO. There was a really good explanation and thread about that in general around here recently I read, saying that essentially there is a million other things to consider and worry about before worry about the TIMBER match of one speaker to another. If remember where I'll dig it up, It was a post from a calibrator or Dennis or Nyal or something like that I remember but I can't remember which thread and person... lol. Too much AVS for me and too much reading, I'm starting to forget more than I know.
EDIT: Looks like someone snuck in just before me ^ Yup. What he said.
"Too much is almost enough. Anything in life worth doing is worth overdoing. Moderation is for cowards."