I know this is probably a more manufacturer specific question. I'm looking for some bookshelves, I'm keeping an eye out for a pair of studio 20s on the used market, I'm in no hurry to buy. These will only be used as stereo speakers for the next few years at least. (I'm a student, and I move a lot, so no big home theater for me just yet) My concern is that I don't want to fork out ~$1000 but not be able to timbre match a center channel to these speakers when I buy one some years into the future. Paradigm seems to update their speakers not infrequently, so I'd be concerned that in 5 year's time the center speaker available in the stores might no longer match. Is this a legitimate problem, or does version changing between otherwise meant for each other speakers not matter much? thanks!