Sonus Faber Amati Trads or Serafinos + Gravis Vi?

I am considering upgrading my speakers from Harbeth SHL5+XD to either the a pair of Amati Traditions or a pair of Serafinos with a Gravis VI sub. Each combo comes out to about the same price (with one Gravis VI sub). Room is 28’x16’x8’. Gear is Mac C2700/MC611s/Esoteric N-01XD. Just for two channel music. Mostly classic rock, vintage country, classical, rhythm and blues.

Any thoughts on which combo? I can audition the Amati Traditions and Serafinos, but not likely with the Gravis Vi sub. Could demo with a JL or a ML Balanced Force. Does anyone know if the SF Gravis subs are truly matched to the SF speakers? Or would it be better (other than for looks) to go with a JL or ML Balanced Force sub?  And is there an advantage with a dual driver design like the SF Gravis VI and ML BF vs a single driver design like a JL and REL?