There is no absolute correct choice.
Results will vary per one's system components, location and AC cleanliness.
Personally, I have found the best place for cable upgrades in the following order.
1) Interconnect between source and preamp.
2) power cable on Dac/CDP, preamp, lastly amp.
3) Speaker cables.
4) Interconnects between preamp and amp.
In your specific system, (not that there is anything wrong with it the way it is) the weak link might be your Morrow Audio MA2 interconnects, followed by the Audience Forte F3 power cord.
The important concept here is to make an educated guess, bust a move when you find a good opportunity and learn from your decision.