I moved "up" from the 3.6s to the 20.1s and like James63, I noticed way better bass and an overall fuller sound. They were purchased used for about $8,000 and I have never regretted the move. Your room should be plenty big enough to let them perform the way they should. Mine are driven by a pair of Krell fpb 350's and even with that, I think they could stand twice the power. Mye stands are, IMO, a requirement for getting the most out of Maggies.
Go for it - you won't be disappointed.
Go for it - you won't be disappointed.