I've got a 10 year old 2.5XT turbo Forester, and my wife drives a 9 year old 2.5 Impreza Sportwagon RS, and we hammer them mercilessly.
Well, at least I do. My wife's a bit gentler on hers...
Neither have had any engine issues whatsoever, and I've never heard about head gaskets being a problem with H4's.
I have the utmost faith in Subaru flat 4 engines, and I'm expecting my FA20 to live long and strong too.
In a combined 19 years of Subaru ownership, we've had to replace a clutch on the Impreza and rear shocks on the Forester.
Other than that, only routine servicing and tyres.
