Knowing cute "STEP THREE" would probably requires some fancy custom re-cables or a extension to get it to S500 killer levels.
You lost me on "STEP FOUR" Profit??? As in yeah baby, i scored big by getting these "Giant Killers", saved me some serious Cha Ching$$$s!!! Profit BABY!!!
It's a South Park reference/internet meme.
But yeah. I can't say for certain how it compares to the cute-modded HA-S500s, but I can say that without any mods (other than the pad swap) the EFi-82 MT dominates the Brainwavz HM5. Seeing that the Brainwavz HM5 has been said to be a poor man's HD600, and that the Somics completely destroy them, it's pretty amazing sounding as-is.
Profit means that you don't have to spend $100 on these $40 headphones to make them sound awesome, but if you want to, that's A-OK!