With the higher end subs, the quality of low frequencies at the listening position should meet or exceed that of the larger speakers. After years of having those massive floorstanders (100s), and suffering with trying to achieve a flatter response at the listening position, I switched out to the Sig S2s and a rhythmik sub, and have had a lot less issues to deal with (nulls and modes). Everything is seamless and tight tight tight. To each their own, but there are other things I'd rather spend money on instead of the massive array of redundant drivers in the S8s and 100s. You need the sub anyway, so just get the best one you can afford.