Sounds like a lot of money for a 16-year-old Subaru, I would think about 1/2 that would be about right. As far as reliability might be OK if it has manual transmission and head gaskets have already been replaced, assuming it's normally-aspirated 4-cylinder. Turbo engines don't have the head gasket problem but at that age turbocharger replacement is likely needed not far down the road. (Run away from Subaru 6-cylinder engines.)

I would be very hesitant the thing is it does have a turbo which is a massive inconvenience to you. Replacing a turbo is likely going to cost you at least $1000 possibly even more. A reason a lot of cars have issues with a turbo revolves around the fact that the other components really need an upgrade overall compared to a naturally aspirated engine. At your price point around 5-6k i am assuming do NOT get a turbo car. Old school turbocharged cars are dirt cheap because how much of a liability it is.

a naturally aspirated v6 car is likely going to be overall better than a turbocharged 4 cylinder. An acura tl might be an option for you

Subaru has issues with normal aspirated engines (blown head gasket), is you add turbo to it, imagine how terrible it will get. Also it is a 16 year old Subaru and assuming that it is automatic transmission, you should completely pass on that car unless you hit it dirt cheap.