Ron, you need a louder exhaust

 

are you out of warranty?

 

Though it has been continually stiffened/braced ( and as result become heavier and heavier ) over it's 40 something years, the 911 chassis is not up to current clean sheet computer aided design chassis stds as the basic architecture is very old. It requires ever stiffer suspension to compensate for modern tires and increased power output , in order to continually improve handling to keep up . That creates more resonances which equals rattles as a trade off . Aftermarket susp that improves the handling will only worsen it.