Sub woofer in boot / trunk storage compartment

Hi,

I am just wondering if any body has done this. It has been done in E 90s. A 8 inch or 10 inch subwoofer is mounted in the storage compartment where the spare tire kit is. The reason I asked is that a touring has servo mounted in the compartment where the AMP is. It would be difficult to install a sub woofer enclosure there.