I can't remember all of the mods off hand that I made to my Dac 60.
Basic mods that yielded good results.
1) 4 Fred bridges. PS, DF supply and DAC feeds. This was very worthwhile!
2) All Power supply caps and added a choke. Also did the supply caps that feed the DA.
3) added .1uf Film caps on some of the other Silmic.
4) upgraded jacks
5) tubes
6) Upgraded the Output caps and some resistors
Stock, the Dac 60 is a fine performer for the $$, modded, resolution is kicked up. Finally through in the towel and said enough. I did flirt with upgrading the regulators though and with winter approaching, might be worth investigating.