I think for jazz, the XA series is probably better. The X 0.8 series sounds faster and has more slam but I would think the XA 0.8’s excel in every other way so it would depend on what you prefer.
The X 260.8 are mono’s right? They will take some heavy lifting too.
There is a lengthy thread here where the OP goes through many amp permutations and he reviews the the X350.8 as well as some XA 0.8 mono's, with a combination of pre's and speakers. i think he is currently on the ARC Ref 10 and some Wilson's so it may give you an idea.
The X 260.8 are mono’s right? They will take some heavy lifting too.
There is a lengthy thread here where the OP goes through many amp permutations and he reviews the the X350.8 as well as some XA 0.8 mono's, with a combination of pre's and speakers. i think he is currently on the ARC Ref 10 and some Wilson's so it may give you an idea.