Cheers SeanBloody hell Jim, How did I miss this thread, you make me look lazy, love some of the stuff you are doing and plenty of it is on my list, especially the sub upgrade, top stuff and great attention to detail, both interiors are totally transformed and look brilliant
I've actually built another sub box as I was planning on having a similar setup in both my Z3s, but one was going to have a 6" and the other an 8". I purchased a JL Audio 8W3v3 sub, and after trial fitting (in as many ways as possible) it just wouldn't fit, due to the depth of the speaker - the magnet was just too big. I therefore am just going to swap the 6" sub enclosure I built between cars as I drive them. Its a 30 second job to remove the sub box and attach the wires.
Point of this is, I do have a sub box in bare wood form with an unfinished lid that I have going spare. Let me know if your interested and I'll put up some pics of it.