|for oil temperatures measured at the turbo inlet and outlet lines. Personally I have my oil temp sensor mounted in a sandwich adapter, another common location is a bung in the oil pan itself. Both locations will have less temperature variation than you would probably see directly at the turbo lines.
I usually see oil temp on par with coolant temp during normal driving (even boosting), and I've only ever seen oil temp come up much above coolant on the track (I think I saw 250*F). I do have a larger aftermarket oil cooler.
Curious, what kind of differential do you see across inlet and outlet?
I'd start to get concerned above 300*F, but I'm not sure if the temp at the turbo outlet is as concerning compared to if the sump oil was at 300*F.