Magnepan MMG for fun and enjoyment.

I think it would work all right... The only real way to tell is to try it and see. I say "go for it." They might sound pretty good with the Manley amp in your smallish room.

I'm using MG12's in my 13' x 14' listening room. I have the speakers about 41" off the rear wall. Can you afford to use that much room. This was the sweet spot in my room. I listen to them angled inwards position and sometimes facing forward. Each position has it's virtures in soundstage presentation.
I'm also using a 35 watt tube amp and YES, they sing in my room. The MMG's should be wonderful in your room especially with the amp you have.

I just put a Hafler Transnova 9300 in my system to check it out for a friend and I got a wonderful midrange but the highs were all wrong. The speakers will tell you what is upstream. You will be able to hear the changes that are made too.

I agree with Plato, give it a try. You may be very surprised. The Manley is very good and should mate very well with the Maggies. My room does not like speakers that have bass below 35 Hz. I can use a subwoofer just fine but not a speaker that goes below 35Hz. Things get fat in the bottom end. Strange room I say.

I do not get it, you have two systems? Is there a question about the Trentes/Stingray?

Interesting. I used to have Maggie 1.6s hooked up to a Stingray. Surprisingly it drove them well. Very vibrant though limited on dynamic range, the Stingray is quite nice.

I also used to own the Trentes and ran them with my Audio Note Soro SE (18 watts) A very nice combo. I too loved the Trentes dearly. I preferred them to my Maggie 1.6s.

I think you will have a nice set up with the Stingray and MMGs (if that is what you are doing). I think you will find, however, that the farther out into the room they are the better they will sound. I have consistently found Maggies like to be as far into the room as they can be (up to 7 feet).

have fun