I need to go back and read this entire thread, I have a Pro 500 I have always been curious about updating and modding. Have you ever browsed on this site?
http://www.musicalconcepts.com/Haf_pwrmods.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;
The larger and toridal transformer and output caps I would think have to help, but I ain't a tech of any sort, but it sure looks cool.
Jim