Update on my particular situation:
Took the car to the dealership, they were courteous and professional. Asked them to address the coolant leak, clutch judder, and do an alignment, which the car needed.
The verdict on the coolant leak was a head gasket. They replaced the left side under warranty. They called and asked if I wanted a new timing belt for the cost of the part--$60. I said go for it.
The clutch problem they said would cost $1100 for new clutch and flywheel. Because it wasn't a "safety issue" they would not cover it. I told them to forget it. I can get used to it, I suppose.
I am satisfied with the job they did on the alignment.
Spent $142.00 and I hope my car is good to go for a while. I think my opinion of Subaru reliability has taken a hit. New head gasket after only 53k miles? Glad it was covered under warranty, but WTF? My old Mazda must have spoiled me--170k trouble-free miles and the original clutch when I sold her.