E46 M3 Convertible: Ok? to cut 3" or 4" hole in rear speaker area for bigger speaker?
I'm trying to install a deeper speaker than stock into the rear side of my 2003 E46 M3 convertible (see photo-hole would be to remove the circular depression on the metal). I would need to create about a 3 or 4 inch diameter hole in the sheet metal behind the current speakers on each side of the car (see photo). There seems to be a gap of empty space between the sheet metal behind the speaker and the actual body sheet metal of the car which is further behind.
Does anyone know how much space inward space I could get if I made this hole? (I need about 1 to 2 inches)
Are there any vital mechanisms or wires that can't be moved to the side so the new speakers can fit their larger rear magnet protrusion?
Lastly, would this affect the car structurally?