Given it condition, how difficult will it be to change? When it does fail what code will be thrown?
Command valve for the wastegate, as indicated by @GCroyle
It's not hard to change. You will get boost related faults, thou I can't recall the exact code.
I have already replaced all my brake lines, front and rear differential, from rust.
The suspension is ok. I'm going to have to treat the frame at some point soon.