[r33_RGSport]

I have done a research on how to get this done and basic cost of doing external sub.
But, my local customer got held up with the improvement that it will make, since the trunk insulation on G30/F90 is very very good.
I used do custom audio system 20 years ago, custom box, wiring, etc.
The only way to get the bass to pass through the insulation is to create a pass through port to the cabin or open up the ski-pass through.