Subaru Outback Forum : “how many miles is bad”

I had a 2000 Outback Ltd, with 203K till 2 weeks ago.  Now I have a 2009 Outback.  I was going to keep it for another 50-100K - but another bad head gasket did me in (turns out that standard antifreeze has phosphorous, which erodes the gaskets.  Subaru now sells a phosphorous free coolant, for $25/gallon). I also had just replaced, again, the catalyst at $1200., and rust was starting to take more of a toll. So, plan accordingly.

GC

I have the same car with the same milage on it...Is there anything else I should be aware of besides the antifreeze?