Coupling Capacitor upgrade? Which one first?

Not too much change. (just a feeling some thing removed :)

Shows you the Wima's are pretty transparent, just leave them be.

Cheers George

I ordered New wimas from mouser, I will try them next week.Maybe my amp input wimas are fake ones. Maybe it makes a difference. 
What do you think which one is more important caps, amplifier input or dac output? 

What do you think which one is more important caps, amplifier input or dac output?

Just leave the amp ones in, and leave out the dac ones. But then only use that dac with that amp!

Cheers George

I agree with all of @georgehifi 's comments so won't repeat them. The only thing I can think of that could affect the sound is if the roll off is close to the audio frequencies. Seeing as all the MKS2 caps come with the same pin pitch, you could try the 10µF version (which would move the roll off further away from the audio frequencies) although I still doubt that would make much difference.

+1 for 10uf
Bass will go down another octave "if" it was cutting off a little too early with 4.7uf

Cheers George