Which types of speakers are ideal against a wall?


I currently have rear ported floor standing speakers (Dali Euphonia MS-4) against the wall due to no other room options.  Are these speakers feasible?   I also have 2 Rel 528s along side each speaker.  I am looking at replacing the speakers.  I also have 2” acoustic treatment w 2” brackets behind the speakers.  Any speaker suggestions in the the 5-7k range (used) welcomed.  

Equipment:
Modwright 150 SE 
Dali MS-4
Rel 528 Qty 2

Room 15 w open wall  and 17 L 
puffbojie
The ports have nothing to do with it, other than contolling volume and efficiency.  The bass wavelengths are longer than your room.
I would advise moving your subs around until you get a balanced bass response with the least room resonance.  You should get good results with two subs (it can be done with one, but you will limit your listening positions).
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The subs need to go against the back wall too.  Any idea if they would be more effective lined inside the speakers or outside the speakers?
I had the Wilson Audio Duette 2's and they had to go against the wall.  They were outstanding.  Sometimes, you can get a great deal on used but maybe still above your budget.  Raven Audio has just launched a new speaker line that you might want to investigate.  Celest Towers for under $5k.  Call James or Dave at Raven.  
Snell Type A's! Designed to be used that way! I have a pair (III's) from the original owner - bought from the Connecticut audio store where I once worked! Talk about serendipity! The Type A III's will KILL just about any of today's over-priced five-figure speakers! Peter Snell got it right!