I've had my amp bolted to the box for ever, no problems
Phoenix Gold QX2180 and a USAcoustics 2200 and a USAcoustics USL4085 bolted to a box holding two Clarion Pro Audio X2 12" subs - One year, subs went pop...

Same Phoenix Gold amp and USAcoustics 2200 amp bolted to a box containing a single Clarion Pro Audio X2 10" sub... Three months, sub VC melted

Same Phoenix Gold amp and an Alpine MRV-T757 bolted to a box holding the PB15