Did some more work today. I now have refitted the subwoofer. The amp that I had in the footwell has been moved. In a moment of genius I realised there is room above the glovebox, as I am lucky enough to not have a passenger airbag. So with the amp relocated between the glovebox and under the dash the subwoofer is back in place. Cool, all totally invisible and sounds ok too.
Now, change the head unit or not? For those of you that have fitted a new stereo, did you make a frame and screw the head unit in like the OEM is? Or are they resting on the console panel?
If your fear of staying alive, outweighs the thrill of making the corner, brake.