Best Sonos ZP-80 Mod?

I have Cullen modified ZP-80 feeding an Accustic Arts DAC MKII into a Cary SLP05 (Tube)preamp into a Bryston 14BSST (600 watts). My speakers are Aerial 10T. All cabling is Acoustic Zen. In an A/B test of modified and un-modified, my wife, a friend and I all felt that the difference is immediate and dramatic. Mod has more transparent sound, no grain and tighter bass. Cannot compare to other mods because have only heard Cullen. However, in my system, well worth the money.