what is the weakest link in my audio chain

Would like to get some advice on the next best upgrade to the following setups. Music playbacks are very important here.

paradigm studio 40 v2 for fronts
paradigm studio center v2
paradigm studio 20 v2 for rears
Hsu VTF3 MKII as sub
Arcam av8
Bryston 9bst
denon dvd-2910
outlaw interconnect
generic digital coax from denon to arcam
HomeDepot extension cord (10AWG) for speaker wires.