I was out this weekend fucking around in the mountains and my oil temps hit 240* in 75* ambient temps, so I could definitely see them even higher on track.

I hit 250-260 deg F on track with na motor, hell I see 210 on 100 degree days with the AC on on the street. It must read much lower with the drain plug temp sensor. My sensor is mounted through the pan close to the oil pickup.
I have two RX-7 oil coolers sitting in the garage, I just need to find the time to get one installed. I only track the car 2-3 times a year, so I have been debating on doing something that would allow me to loop the lines back for the street and hook up the cooler for the track. It is nice to have a thermostat in the cooler itself as well.
If you add any other coolers, make sure you get one that will not restrict flow. I installed a remote filter and oil cooler out of a supra that had smaller 10mm inlet/outlets and my oil pressures dropped by 10-15 psi, not good. That setup did not stay in the car long.