Amplifier power needed by 1.7s

I recently acquired Magnepan 1.7s along with a REL sub.
What tube amp power do they really need to perform well?
Currently I have a MAC MC275 and am acquiring a second to run them as monos. Will this be adequate? Room size is 20x30 with 1.7s about 4 ft. from short wall. I listen about 11 ft. from 1.7s.
I have the Maggie 1.7s with an Audio Research DSI-200 and two REL subs...a good recording will not sound edgy or brittle with this combination...tubes only smoothed out the crap recordings while losing some detail in the excellent ones.
Thanks Auralone

Two REL subs! Do you find using two worth it? I've read discussions on this and opinions seem to vary widely. I've had ARC gear and it certainly is excellent and I would be surprised if you were anything but happy with it.

The effect of tubes seems to agree with my impression of their effect.
I had one REL sub and after six months added did make quite a substantial improvement in depth and ambiance retrieval. I've spent too much money over too many years on trying to make a silk purse out of a sow;s ear (attempting to make horrible recordings sound good on quality systems with expensive tubed gear). And don't let anyone tell you that Maggies do not need a sub!!
I heard the 1.7's with and without a rel sub. Addition of the sub made the 1.7 a much better speaker. I was very impressed. I'm not so sure that tube amps are the answer. I prefer SS with maggies. I'd go for tubes in the source or pre.
Somehow (in my first response) I missed that you already have a REL sub. Everything I've read (and heard 1st hand from an owner of 1.7s and a Rogue Cronus Magnum indicates that that is an excellent amp/speaker match. After that, add a second matching REL sub. Two subs blend easier and give you more options for smoothing out room node resonances.

My experience with twin subs matches Auralone's. I started with a single sub in November with my 2-channel system with Mirage speakers. Three weeks later I added a second. Adding the second one unexpectedly resulted in much more 3-dimensional imaging and more perceived space around the voices and instruments.