don't get hung up on the piston/ringland issue.
it's an issue on all 2.5 models.... hawk and Hatch. but not everyone fails.
you only hear about the 'problem' from ppl when they happen.
wrong fuel used, bouncing off the red line, not serviced regular etc are all factors that can cause it.
touch wood & famous last word.... my car is fine 5yrs old now.
I'm still under subaru warranty (only cost £608 this yr, so a no brainer really).
worst case scenario, throw £5k-ish at the car, gets it all sorted and you'll see 400bhp easy.
£5k is a fraction of the cost it would cost me to change the car for something thats not as good as what I have.
Plus.. plenty spend on their car and spend more than that on stuff they don't need anyway