Charlie has the ELPAC WM-075-1950. He has compared the modded ELPAC WM-075-1950 to the stock one. He has not compared the WM-220 (stock or modded) to the WM-075-1950 , as far as I know.
The WM-220 is a very good PS for the money. I do feel the mods improve it, but I am a bit biased

I also find the the differences in power supplies are more audible with a modded SB than with a stock one.