Subarus generally should be reliable MagnetON.. as long as they are shown the service bay when the time is due.
Not so long ago, I worked for the largest Subaru dealer group in Australia, living just above the service workshop of their main location.
Generally there arent too many problems with them, but they have been prone to be finicky on fuel. There have been people putting that ethanol blend in them, and it causes the head gasket issues that Gordon Streeter mentions (the techs reckoned it burns hotter & warps stuff.. who knows..)
While anyone who thinks increasing the boost without regard to anything else deserves the trail of white smoke and oil out the back
That said, the turbos seem to be a good product, but seemed to last a lot longer if you idle them down after hard owrk or long runs.
The biggest issue that seemed a repeat offender, under warranty anyway, is the front diff wearing/failing. Its not a cheap fix, and any noise should be looked at right away as it can be something as simple as noisy bearings, but more regularly the sign the whole unit isnt well.
And make sure you have a super strong battery in it. The poor little flat four is great at making engine power, but not so much battery power. They seem to have put a too small a CCA battery in there, as warranty complaints that were refused & made it onto negative NPS scores were mostly around battery failures inside the first few years of ownership, and a second failure before the warranty ran out... <2 years of life..