1) the trunk of a hatchback is really is not sealed well enough

I think in the X5 we are talking about the lateral wall being sealed from the trunk area and the interior of the car. Those "cubby" holes are pretty air tight from the rest of the cabin, you can take one off and close it to appreciate the seal. And from what I have seen, the sedan rear deck installs, are less sealed than these compartments.


2) the drivers really do need the benefit of a tuned enclosure

Woofer travel is a major problem with infinite baffle design. I am sure however, technology has improved as i stated over the past 15 years. I could break down the necessary specs, and give data of the changes that have taken place, but as I posted there are some companies that have designed IB specific woofers with the necessary specs.

If I can find a spare set of lateral wall covers, I may attempt this. I do still have a fiberglass itch that needs to be scratched every so often. Nothing like catching a fiberglass box you made 10 years ago show up on ebay.