I have an 01 29 fever I took the silent choice off and put on new 4 /12 tail pipes and now at 1000 rpm I have A hull vibration it sounds like it goes away at around 1600 rpm but it's loud around the docks and when I am idling out, I don't want cause any damage to any parts or anything coming loss. Any solutions?

no rubber grommt around the mounting flanges or not a good enough one.

Mine vibrates the swim platform at idle. When I switch to the silent choice it goes away. As you mentioned it is only an issue at idle.
I always use the silent choice when I am putt putting along (No Wake zones).