Subaru Problems

The oil consumption is a result of the engine design, being horizontally opposed, and it's not limited to Subaru. Oil accumulates in the rings when it's sitting and you'll sometimes see a puff of smoke from the tailpipe on start-up. It's not something to be concerned about if you check the oil on a regular basis, as you should do on all cars. Use the Subaru recommended oil when topping it up. You'll find that in the owner's manual.

If you are not doing many kilometres, which you obviously aren't, I would suggest you service it every year or 10,000 km, whichever rolls around first.

The oil consumption is a result of the engine design, being horizontally-opposed, and it's not limited to Subaru. Oil accumulates in the rings when it's sitting and you'll sometimes see a puff of smoke from the tailpipe on start-up. It's not something to be concerned about if you check the oil on a regular basis, as you should do on all cars. Use the Subaru recommended oil when topping it up, you'll find that in the owner's manual.

We checked with Subaru and were told that you should follow the manufacturer's recommendation for engine oil as specified in the owner's manual. Subaru also told us that 0W-20 engine oil is available in Australia and can be purchased through Subaru dealers. They also said that you could rest assured that although the engine will not be delivering maximum power, maximum torque, best fuel economy or best exhaust emissions, no harm will have come to the engine by using 10W-40 engine oil.
 

I would ask the dealer to demonstrate that it is an induction noise, if necessary by driving other vehicles, which should have the same noise if he is correct.

Rear diffs on that model Forester are known to be a problem, even at low kays like yours, but it's important to make sure it's not a wheel bearing that's making the noise. Your mechanic should be able to identify it if it is a wheel bearing issue.

They are known to wear, but you need to have them properly assessed to confirm that the problem is with the diff. The prices quoted by the Subaru dealer would appear to be reasonable, and their diagnosis also seems reasonable, so I would be taking the car to them before I had a new diff fitted.
 

It's common practice to replace the water pump at the belt change, and not just on Subarus, as the water pump is usually found to be leaking when they take off the front cover and belt etc. By replacing it when the engine is pulled down for the belt change you won't have to do it again when the water pump finally fails. If you're not sure ask to see evidence the water pump needs replacing before the mechanic goes ahead and fits a new one. $400 is about right if it has to be replaced.

When Subaru updated the Transmission Control Module in 2010 it did what it thought was needed to fix the problem, but clearly they discovered later that the problem was with the torque converter. All of that suggests the company was being helpful in trying to fix the problem. Now they are offering you a new torque converter, leaving you to pay the cost of fitting it. That's a fairly standard deal with a car as old as your daughter and son-in-law's, and I would accept it.