Thanks Lolo78. I worked pretty hard on my system and it lead there!
Magnepans as with most planar speakers hate lots of connections in the signal path. So if you can try to wire things as direct as is possible.
For instance on your external xover you have an input on binding posts then through the xover to the outputs which are on binding posts, then to speaker inputs on binding posts on the back of the speaker then solder points for the fuse etc. They all add up adding haze and gunk.
Magnepan also use fairly cheap posts and tend to have many unnecessary solder points. See how brave you feel and bypass with nice wire if you can.
I had a pair of MG3.6Rs and did all the above including remaking an external xover with nice parts in a bigger box. It became a whole new speaker with lots more resolution and much more refined in every area. It didnt cost too much and the rewards were well worth the trouble. I loved them.
Where possible hard wire bypassing connectors/solder points. If you remove some of these contact points you will find a drop in noise which will bring more naturalness, detail and dynamics. The bass texture and tuning will blow your mind! An extremely capable speaker.