The air filter on my mirage was rattling, and getting worse. You could hear it inside the car, it almost sounded like it had a rod knock at idle. The rubber parts put in place to keep it from vibrating had worn down too far.
I have a 3d printer capable of printing flexible materials. So I printed up a set out of TPU and installed them about 10,000 miles ago. Here's how they looked when I changed the spark plugs Saturday:
I don't know if anyone else has a rattly air filter, but this seems to be a decent solution.