I would have to say its got to do with the exhaust system when the engine goes faster their is more torque its mounted on rubber mounts so it twists to one side . This in turn seeing that the exhaust system witch is also mounted on rubber mounts moves to and starts to rattle on the frame or body part. The only other thing I have seen is the catalytic converters will rattle before they go bad and clog but your's isn't old enough unless you have problems you haven't mentioned . Check the alignmet of the system first
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I would have to say its got to do with the exhaust system when the engine goes faster their is more torque its mounted on rubber mounts so it twists to one side .
This in turn seeing that the exhaust system witch is also mounted on rubber mounts moves to and starts to rattle on the frame or body part.
The only other thing I have seen is the catalytic converters will rattle before they go bad and clog but your's isn't old enough unless you have problems you haven't mentioned .
Check the alignmet of the system first
Noise is best diagnosed by tech ears on the noise, not over the internet. Sorry just to much of guessing game