this seems to be working out good so far.

If I were to do it again, there would be two things I would change

first I would use 1/2 inch MDF instead of 3/4. this would set the woofer back about 1/4 inch. or if I had a router I could have set the woofer into the mdf 1/4 inch to make it flush with the surface.

second, The subwoofer has to be as high in box as you can get it. The set up I created the very bottom of the woofer is at the very bottom of the interior cover and making a sutable grill might be challenging.

__________________
BMW Level 1 Tech