Is it normal to need your head gaskets repaired/replaced at only 80,000 miles? Now at 100,000 it needs the tie rods replaced. Is this normal or am I being taken advantage of?

Subarus have a bad reputation for failing head gaskets and if it has that Boxer engine, there are two head gaskets. Also, at 100,000 miles the timing belt should be inspected for replacement ($1500 @ dealer). It might be cheaper at this point to replace the engine or trade it in on a non-Subaru vehicle.

The car is also 18 years old. Nothing abnormal to need these repairs.

My Jeep is way older than that with twice the miles, hard miles, and it has never let me down once. All I do is regular maintenance and feed it lots of gas. I think Detroit should melt down all those failing Subarus and build more Jeeps. No offense intended, just reporting the truth.

But then Jeeps would need new head gaskets every few years.

F_O_R is correct that an unusually high percentage of the 4.7, V8s experience failed head gaskets. That's the way it goes in all engines that have aluminum heads and cast iron blocks because aluminum expands and contracts three times more than the iron to which it's bolted. And overheating any engine is never a good idea. However my Jeep has the all cast iron six, a proven design that originated in the 1960's Rambler American. The only failed sixes where redesigned and cast in China a few years. That problem explains itself by saying China.