Helmet and Russian Circles also set to play
Tom Morello also appears on John Dolmayan's all-star take on "Street Spirit"
Kirk Hammett, Tom Morello, Youth Code and others celebrated in style
Polish musician shreds "Toxicity," "Symphony No. 5" on acoustic guitar
Band even rehearsed cut "once or twice, thinking of releasing it as a System song"
John Dolmayan's These Grey Men project to finally release star-studded debut
Ohio fest's stacked bill also features Bring Me the Horizon, Lamb of God, more
Band broke out 'Steal This Album!' cut during hit-filled Reading Festival set
10 Second Songs' Anthony Vincent channels Serj Tankian and Co. channeling Freddy Mercury and Co.