Dave Grohl to Sub in for 4th Annual 'Acoustic-4-a-Cure'Dave Grohl to Sub in for 4th Annual 'Acoustic-4-a-Cure'Dave Grohl will serve as the co-headliner for the 4th Annual 'Acoustic-4-a-Cure' benefit after James Hetfield had other touring obligations.Chad ChildersChad Childers