The only real place you want to ensure a seamless match is across the front three speakers It just sounds plain odd if the center doesn't match. Surrounds don't matter quite so much and subwoofers, less still.
Subs don't really have a tonality of their own, so 'voice' matching is neither necassary or indeed, possible. They just deliver the low frequencies, with the tone, or rather character of the bass note being delivered by it's higher harmonics which are delivered by the main speakers.
Further more, there's not that much to be gained by demoing subs. Their performance is utterly dependent on the room in which they are demoed and their interaction with it, so unless that room is yours, it'll only let you know which one will go deeper or louder. You could probably work that out from the specs, or by looking at the size of the thing.
I'd suggest that you can do a lot better than anything Kef or REL can offer at this end of the market. Forum favourite BK Electronics offer the
XLS-200, as a for instance, and it's an extremely popular sub round these here parts. Think MJ Ref 200, minus a couple of knobs for less than half the price and you're in the right ball park.
Use the forum search facility and you'll be overwhelmed with threads to read.
The visual match is something only you can decide.
Russell
HC6000, 88" Carada Criterion, PS3, Sky HD, CD52 II, 8000AP, 8000P, RB-985, GB1 & TB2M-C, Xenon 25 Surround & LCR25, Monolith DF, SMS-1.
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Monolith DF subwoofer. B&W VM1 speakers x5.
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