Yes I understand the nervosa.. I put BG's in my cd player, I removed cheap computer grade caps.
What I got was a very clean background, tremendous detail, great bass...for now
I lost some roundness and romance, will it come back? who knows I will wait a year, I changed 8 caps, some of them big BG's, that's why i say it is a balancing act, sometime puttingthe best in a circuit that was not voiced for it may not be a good idea.
But give it time, it will improve, you just have to be honest with yourself and see if where you landed was where you wanted to be. Keep the old parts, you may want them back in one day.
Is the W4S a ICE amp?
Mike