REL #25 or Stacked G2s

My current setup is Magnepan 20.7's with a pair of REL G2's. I'm thinking of adding two more G2's or trading and going to a pair of REL #25's. Anyone have experience with the #25? Any thoughts?  Please don't offer suggestions for other subs. I am very happy with REL. They're amazing and work beautifully with Magnepan.  The room is a good size. 18x25 but kinda open in the back. Only a half wall and then an angled 8ft opening.
Ag insider logo xs@2xjackcoke
I'd look into a pair of stacked JL e110's (4 total) with the CR-1 crossover.  The two on top only for better modal coupling in the room, not for output.