The oil cooler is thermostat controlled. Its a 75 degress celsius type (167 fahrenheit)
The exhaust system do not seem to improve the performance. But it feels like the turbo spools a little bit earlier. But it is probably related to that you can hear the turbo some more out the back, and its all in my mind
I can try to make a gopro video with the sound from the JT exhaust, if anyone is interested.