Magnepan 3.6 or 3.7

Magnepan has switched glue twice. The first time it cured the problem of delamination due to excessive UV light. But the problem of delamination due to excessive moisture remained until 2005, when Magnepan switched to 3M 30NF. It is available from them, or you can buy it locally.

Have two systems at home and reside in an area with many  dealers where two are very good friends. Ok I feel very fortunate in the ability to take things home and have direct comparisons from two dealers.

The Maggie 1.6 is a very under rated speaker when compared to the 3.7 I have both. tried a 3.6 very nice. 
Recently purchased a 3.7i NEW  and I am extremely disappointed.

I have the luxury of swapping out the following amps
Audio research VT 100 mkIII  and a VT 100 and a Bryston 4B3 cubed 

The Maggie 3.7i does not play as loud as even the 1.6 FACT
The Maggie 3.7i does not deliver quite the bottom end as the 3.6 or play as loud.

Yes I use two Rell s212 however there seems to be a tiny merge type sound gap thats being picky here but for comparison sake I must say this.
I have a Rell t-9 works well if you want a tiny touch of bass as a gap filler if you use the high inputs. 

I am aware it is very difficult to accept a 1.6 playing seemingly more volume than a 3.7i but that is a fact.

Best match up with the maggie 3.7i was with the following gear
Audio Rsearch Ls 5II " fine pre amp" and the Bryston 4b3 and a T9 rell ok two s212 better but expensive


Honestly a Vt100 MkIII and a McIntosh c2500 was very good
with a Bryston 4b3 amp better 

I would stick with a 3.6 and be done with it if had to do all over again.
I am going to trade in the 3.7 and step up to a 20.7 

3.7i cannot be bi amp and if you have a 4 pin speaker wire at the speaker end, start calling the dealer to modify the cables which I was not willing to do because I am looking into other speakers or if the 20.7 will accommodate the current cables  I will go ahead with the 20.7.

I have to say Maggies take a long time to break in. SO I am hoping your new 3.7i have time to fully blossom before you trade them away. Comparing fully broken in 3.6 to new 3.7i is not fair.
The 20.7 also are not biampable, nor biwire. I would say you can use the biwired cable, just use both into the one set of inputs. (perhaps with some adapter)
I went from the 3.6 to the 20.7 and can say the 20.7 have a far better midrange clarity and power, and the bass is stronger. But they also need months to break in fully. My positive when they were new was the increase in midrange transparency. Otherwise the break in period was annoying.. Lack of bass, no low level detail at lower playing SPL.. all break in related issues.
I almost also went from 3.6 to 3.7i Magnepans, but I thought that was too much only a lateral move... and decided to make the big leap to the 20.7
Glad I did. Now, over six months in, the 20.7 are more sensitive, play softer and louder with more detail... better than the 3.6 ever could.
I also kept my amp from the 3.6 Bryston 4B-SST² and am completely happy with it. Really moving it up a notch getting Furutech AC duplex.