2002 996 C2 65k mile, coolant tank replacement
1) Use method of your choice to remove coolant below the coolant tank.
2) Remove air cleaner, air pump.
3) Lower engine (really not that bad) basically put piece of wood on jack. jack point the small 2 rectangle shape behind the oil pan, jack up slightly to put load on the jack. (lift the car suspension up 1" or less NOT the car tires stay on ground)
Unbolt the two 18mm engine mount bolt. Make sure the jack is solid, you can stack something on the both sides under the oil pan (old phone books, wood ..) just in case your jack gives out.