Hi Dave!
From what I can remember, the soundaktor was just bolted in on a bit of a flimsy bracket but it’s only a small, lightweight unit. I made sure mine wouldn’t rattle again by tightening everything up, including securing the wiring, and using some insulating tape to deaden some vibration.
I don’t mind little almost cost-free fixes, but what I’m not about to do is spend a small fortune replacing the suspension to cure a knock that shouldn’t be there.
Hope your wife enjoys the new car!