i think running an oil cooler would have a good advantage over stock as long it was a thermostat operated one the ones that don't run thermostats make the oil to cold
also from a t18
i would recomend u use the t18 one as the slave is opposite the exhaust
differences
ae86, ae71 t50 = 20 spline
t18 = 22 spline
ull need a t18 front half shaft to use the t18 box
incorectomondo
this is the way i would recomend to do as i did this in mine if u don't do it this way u will end up with drill holes all throught ur firewall