I mostly drive my car on the street and have had no issues from excessive heat build up over the norm. A few things to keep in mind, none of the old school diffs or other aftermarket diffs available for our cars have cooling fins either, aluminum dissipates heat faster, we are now using synthetic gear oils compared to old school which are much better, plus you would create higher temps on the track then you would on the street. I am also changing the oil in the diff more often. If I do notice any issues along the way, then I can always install a diff cooler. But so far everything looks good.
