For aesthetics? Guess if you're going the whole S/C route and want to keep with the originality, then put the
oil cooler in. But if you're going to go to the trouble of installing it, hook it up with the thermostat so it works, and is practical for street use.
I didn't go the whole original S/C route and left the
oil cooler off. 9 quarts of 10W30
synthetic keeps it cool enough.