I got to step in here on the oil cooling bit....the oil cooler was
put in to make the engine run cooler...it seems that the early
prototype 4 cylinder VW engines did not have an oil cooler and
relied solely on aircooling. Unfortunately, they had a life of
10k miles or so. The oil cooler was added and engine life went
up VERY significantly. From what I recall, the oil performs
approx. 40% of the cooling on a VW engine. 

Ric