This is what it looks like at the moment:
I deleted the intake resonator, and was disappointed to find it didn't increase turbo noise!
In the process I found some loose hose clamps on the intake hoses, but this hasn't fixed the CEL. I've noticed the car doesn't seem to lose any power or run differently when the CEL is on. I still haven't pulled the codes.
Currently investigating if knock sensor and o2 sensor are the same as those items I replaced on the 02 NA Foz a couple of years ago.