I agree - None.
Very few engines actually need an
oil cooler. Fo the vast majority of cars, the
oil cooler prevents the
oil from getting hot enough to work right, and it creates weight, complexty, cost, and failure points that you just don't need.
Oil is heated mostly by sustained rpm's. If you race on road courses, then you can probaby benifit from a cooler. Otherwise, don't bother.