2 Krell fpb700cx or Krell fpb750mcx

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 (-; 
I had a 700cx and upgrade to 750mcx monoblocs.  Worthwhile improvement!  Make sure you get them new capacitors and put them in top amp stands. 

Also, the Krell Phantom is much better than the KCT.  I compared both in my system and bought the Phanton which I had for several years. Recently upgraded to CH Precision L1+X1.
I had the Krell dealer perform the recapping of my 750mcx monoblocks and also install furutech power cable connectors, so I will be trying different power cables.