I'm not sure if it's been addressed, but the first thing that you need to replace are your thermostat housing and water pump. The fins from the pump are plastic, and the housing is plastic as well. If these bits aren't addressed and replaced with the new metal housing and pump, then it's just a matter of time until those pieces fail.
Congrats on the E36, it certainly is a great handling car with its near 50/50 weight distribution. These cars definitely have great potential. Here's a pic of my late 325i (RIP):
