2 Krell fpb700cx or Krell fpb750mcx

Hi.
My curent setup is krell Fpb700cx - krell Kct - Krell 28cd - Jbl Everest DD67000.

I Think of ading a 700cx and byamp.
or mayby the 750mcx mono bloks in-sted.

Do you have any idea on witch setup will
be the best performing setup.

2, 700cx byamp / or 750mcx monoblok?

All thoughts and ideas a welkome (-;