Compared to the VS you have, you will think the Maggies have NO bass. So the sub is a must for you. With the 1.7 or 3.6 you will notice a much larger sound field. Imaging will be a bit less, but you should have a more "there" impression, especially on vocals. Be prepared to turn your volume knob up a lot more.
A question for Maggie owners
I am curious about Maggies in the $3-4K range. I currently have Von Schweikert VR-4JRs fed by Wyred 4 Sound 500 monoblocks, a Modwright pre-amp and a computer based source. I have always been intrigued by planar speakers and a friend of mine sold them out of his store until the store closed. I know the entry level Maggies have a return guarantee but I am sure that they are not everything Maggies can be. What are your thoughts on switching speakers? I am used to the bass of the VSAs, but have a very musical Hsu subwoofer to pair with them. I am satisfied with my system and I am asking out of curiosity and can buy the Maggies to try but don't know if it is worth the effort.