I have a factory fitted set of centre gauges in my STI.

Can you let me know what the oil temps should be???

Currently it sticks at around 70 Deg while normal driving and can get up to nearly 90 Deg when sat in traffic.

Is this about normal

 

Sounds OK. Do not drive hard until 60-70cent oil temp. In winter even after 15 mls of gentle commuter traffic I sometimes struggle to get to 65cent. Subject to ambient 70-85cent in cruise up to 4000rpm. Very fast road work, lots of gear changes and highish revs 95- 100cent. Hard track, perhaps 110cent. Driven flat out on track for prolonged period on warm day my temp can climb towards 120cent at which time I back off or go for fuel.

 

It all depends where you have located the sender. The temps you quote sound as if it is sump located? Your readings sound slightly low from my experience! With a sump mounted sender I get 80-85c normal running and 100+ stuck in traffic - all quite acceptable. With an oil gallery located sender you would usually see slightly higher readings.
JohnD