Which ARC reference component to upgrade?

I have the ARC Reference 3 preamp and Reference 110 amp and am considering an upgrade in the ARC line. I can't do both right now. The question is, which change (Ref 3 to Ref 5SE; Ref 110 to Ref 150) would result in the best improvement in my system?

System:
Ref 3
Ref 110
Wilson Sophia 2
Music Server to Berkeley Alpha Dac 1
Esoteric X01
FMS Nexus cables