Hi Slider -
I saw your rear deck subwoofer and it looks awesome. I'm looking to do something similar and had a couple questions for you.
Did you do the velvet and epoxy method for shaping the box around the speaker mounting rings, and then create a mould?
How did you secure the sub? create mounting brackets that go underneath the carpet?
I'm in Vancouver by the way, and also have a 996TT - hope to see you on the road sometime!