toning down the ps audio perfect wave dac

i own an original ps audio perfect wave dac. i called ps audio about sending it back for an upgrade. a technician i spoke to said the upgrade would increase the resolution of the dac.

i would like to tone down the treble a bit, as i find it a bit treble heavy.

i thought the least expensive way of doing this is substituting caps in the signal path and or replacing the metal film resistors with reiken carbon fibers.

i am not familiar with the "sound" of caps, but would like to soften the treble.

the only caps i am aware that might do that are audio note, mundorf or duland. am i on the right track ?

if not, what other caps could i consider ?