I have the DSP3100's in a similar size room and will (bravely) step forward with a different perspective. I agree with all the posts that the 5200's in an A-B comparison at a dealer showroom, with good acoustics and speaker placement, will win every time. The 3100's sound lean compared to the more effortless and full sound of the 5200's. However, when you get home and have to deal with the challenges of speaker placement and room acoustics, the 3100's crossed properly with good subwoofer(s) can sound amazing when you get the placement right. When the single woofer in the 3100 is relieved of bass duties and can just concentrate on the mid-bass and up, the midrange (particularly voices, guitar, etc.) absolutely comes alive with these speakers. I also think having all 5 speakers the same makes a significant difference with Trifield. With my old analog speakers (rear speakers different than front), I really cranked down the rear speaker db's as I could never get them to blend well with the front speakers and the effect at any measureable volume was uncohesive and distracting. However, now with 5x3100's the rear effect in Trifield is fantastic. At the right setting you don't really hear it from the rear, it just reinforces the front soundstage in a very substantial way. To me its a similar sounding difference to playing with the depth of the center channel to that obvious setting where it just "pops". Although the 5200's in the front and 3100's in the rear would seem to be a reasonable pairing, isn't that a contradiction to the sentiment that these speakers sound very different? Anyway, sorry to ramble but thought I would chime in with my experiences. If you can go 5x5200's with SW1600's there is no question you've made the right decision. If cost and/or speaker placement issues does not permit that, to me it becomes a tougher decision.