Magnepan 3.7 - 3.7i owners need help please

Hello, I have owned a pair of Magnepan 3.6r's for quite some time. I was assured that the 3.7i's were a big step in sonic improvement over the 3.6r's. So, I went and bought a brand new pair of 3.7i's. Got them home, set them up, and have approximately 20 hours of play on them.

I am using the exact same equipment as I had with the 3.6r's which is a Sanders Magtech amp, a Benchmark 3 hgc dac, and the exact same decent quality cabling. The 3.6r's had a partial external crossover and I was bi-wiring. The 3.7i's do not have anything but a single pair of binding posts, so I am using the exact same speaker cable but not a bi-wire version.

What I have noticed it that they definitely do not have the depth, spatial characteristics, or openess of the 3.6r's. They do however have maybe a more predominant midrange but, at the sacrifice of the midrange being bloated or muddled at moderate volume levels. I have noticed that the 3.7i's have sort of a filter membrane behind the midrange section which my 3.6r's did not. Maybe a smaller rear dipole radiation pattern? The bass is also lacking compared to the bass response of the 3.6r's

The Dealer said they may need more break in to loosen the mylar. However if that were the case, the midrange would get worse, but thembass may get better. The passive crossovers may need some more break in time, but to be honest, i'm skeptical about all of it!

So, anyone out there that can offer some insight would be greatly appreciated. I am just a working class hero with limited financial resources. I cant afford to spend a large sum of money for something no returnable, and go backwards with disappointment. Needless to say I did not get much sleep last night. Might need a prescription for xanax at this point!
 Thanks, Steve..