my QS8s are on the wall using drywall anchors, 3 years and running with no issues.
In the whatever it's worth category, metal studs should drill pretty easy with self tapping metal screws- they don't pre drill when they are hanging drywall, if you're having to force the issue, be sure you're not drilling through a metal plate that may be in place to protect something like a gas line or plumbing behind the wall. Our county codes require metal plates to be placed on the studs wherever the PVC plumbing passes through them to be sure you don't drill a hole into the pipe.
