Bertico0357, at least in my experience, the Cullen mod is worth it. I've A/B'd both modified and unmodified units in front of a modest Monarch DIP>Monarch NM24 DAC>Jolida 302 integrated>Aerial Acoustic 5B system, and the difference is pretty significant. I sincerely wished that were not the case, but there it is.
I've also tried deleting the DIP, thinking maybe there's too much stuff in the signal chain, but it too consistently improves things. IME.
Pkubica, I agree -- it's very very slick and it's FREE.