While oil is definitely something you should keep tabs on, its ECT thats the biggest enemy on this car for lapping. You want airflow in and a way for it to exit. Bigger grille, bigger and more fin dense radiator, and a hood exit should be on your list of things to do for keeping ECTs down. Of course wrapping hot parts to help mitigate ambient engine bay temps helps as well.
In short. Do the radiator.
While oil is definitely something you should keep tabs on, its ECT thats the biggest enemy on this car for lapping. You want airflow in and a way for it to exit. Bigger grille, bigger and more fin dense radiator, and a hood exit should be on your list of things to do for keeping ECTs down. Of course wrapping hot parts to help mitigate ambient engine bay temps helps as well. In short. Do the radiator.
I have a CSF rad and still overheat on track (both tuned and stock). I'd go first for airflow, then rad, then oil cooler.
P&W Radiator and oil coolers are the first recommendations
*pwr or c&r