I installed a pair of those Audiophiler caps from eBay into my Crack. They were relatively inexpensive, and I thought they improved the treble to give the music a bit of airiness. Although I don't have any basis for this, I'm guessing just going from the electrolytic to film made the biggest difference and going from one film to another probably wouldn't make any differences, at least to my ears. Anyway, I'm will be testing out that theory with my Mainline when I replace the stock film output caps with Mundorf M-Cap Supremes.
-Raymond