Magnepan upgrade

@ OP,
Those 3.7's are awful big, but I bet they will sound amazing. I think Zavato's comment worthwhile- maybe adding a sub(s) would give you much of what the 3.7's can do. If I recall, more than half of the planar speaker is needed for bass reproduction, so the much larger 3.7's will move more air than your 1.7's.
B

I've never heard the Eminent Technology LFT-8b planar.
I agree with zavato's first part of his statement, assuming your room is large enough that you can correctly set up a pair of Maggies regardless of their model number. I would also add to that and say if you don't already own a pair of Mye Stands you really need to purchase them to hear what the Maggies are capable of.

Buy Sound Lab Electrostatics and you will get what you are seeking. You can get off the component-go-round. They are a line source single membrane electrostatic that is covered by various patents. Now they have the 545 series that stands 5 feet tall by 25 inches wide. They offer versions that go up to 9' and more on a custom custom basis.

Eminents are great, see if you got a dealer near you. Or call Bruce at Eminent Technology to see if you can get a home trial. I have owned the Eminents for 12 years now and no itch to upgrade to something more expensive, cause that would cost a lot.