I'm not sure someone as OCD as me should have gauges in their car, but it makes sense to check this!
Oil temperature seems to rest at 62-65C on the motorway, rising to about 80 when it's stopped in traffic. Is this too low? I would expect it to be at about 90, I'm sure that's roughly how hot the Passat runs (according to my Dashdaq). It's possible when the sump plug was swapped for the sender that some oil got onto the contacts, so I'll try cleaning them tomorrow just in case.
Boost readings are slightly lower than I'd expect as well - about 0.75 BAR under most heavy throttling, rising to about 8.5 at the top of the rev range. It's got a full blend, toothed belts, GT inlet and still has wedges. I'm sure with that spec I should be making near 1 BAR, or is that optimistic?