I just monitored a 10 minute drive via OBD.
Short term fuel trims are running between 22 and 27%. Occasionally going closer to 0, but most of the time around those high figures. I think I must still have a vac leak, and that may be the source of the noise.
I've ordered a replacement o-ring for the DISA unit, and will get a new throttle body gasket too.
I got a "System too lean (bank 1 &2)" earlier today.