For years I did not use a sub with my 1.6's or MMG's. I recently added a used Martin Logan Original Dynamo with my 1.6's to fill in the low frequencies below 35Hz. I have it set so that you can only really hear it on bass heavy music. The integration is seemless. I don't use a sub with my MMG's which are in my work out area in my basement. They are pushed out to the corners of the room and really put out deeper bass because of the placement and the CDA-254 amp. I have some sound absorbing material directly behind the speakers so that there is no boom.

The Martin Logan Dynamos (the non ported version's) are a great match for Maggies. They are very musical, fast subs that integrate well with Maggies. Used original Dynamo's go for about $275-$325. The new Dynamo 700 and 1000 models go for a bit more. The 500 model is ported, so stay away from it.