I have a 2005 Mazda 3 which drives really well. The only problem with this car is the rusty chassis.
Recently, I either drove over this metal part from some other car or it actually is from my car.
I've heard a bang from the chassis when it happend but this could have been just from driving over it I can imagine.
I wouldn't be worried if my car wasn't rusty. Sorry if this is not a Mazda part and the question is silly.