My Gon NerD60 HHKB I recently built using gold springs:
The key set is DSA Dolch, which at the time of this posting, is available from PMK's shop for a very reasonable price. All switches are 78g, un-lubricated.
The transparent shells are of sub-par quality compared to the original cherry plastic shells, to be honest. When trying to put them on, there's a good chance that part of one of the latches will snap, which means throwing it out and trying again. I do like that you can see the gold leaf contact from the rear, though.
I don't have any non-plated 78g springs to compare with, but they seem very well made and look great.