REGA MAIA 3 VS EXON 3 PAIR

I am using a pair of DYNAUDIO CONTOUR S 5.4 and i would be interested by a rega amp. Will y get and off power whit a maia3 or the exon 3 would be recomended.

Also if i buy one maia3 to begin, can i use it in mono operation in the futur.

Thanks for your comment