Fans should only come on for a brief sec or so only, I've never had mine come on for more than 1 minute even after long road trips/idling. On and off but not the whole time
Smell of gas, is it stock? The down pipe should be the original one with the name subaru on the side that you could clearly read from the right side with the hood open
Did he/she say why the turbo and head gasket was replaced? Timing belt, water pump etc is good but head gasket and turbo?
It sounds like a decent car but I say keep looking but then again I don't know what to say as I'm not there. It's up to you but at least ask why those were replaced if you do decide to buy it