I just got my 02 A4 1.8T. It has an aftermarket Sony HU fitted and the sound quality is not bad but not as good as my old nissan QX.

I'm trying to wire my old subwoofer and amp into the trunk but I don't know how to get the power cable through from the battery into the boot. In my previous cars i simply ran the cable between the front door/bonnet hinge but there seems to be little space in the A4.

Also, where do i ground my amp to? The boot is covered in plastic and I cant seem to find any bolts to ground my cable to.

Any suggestions?