There is an issue with the turbo models which have a recall out currenlty so they can have a remap on the ECU. THe current map is wrong and can cause an engine knock at higher revs. This is only a problem on non-jap spec cars as the europe/UK cars do not get the forged engine internals that the Jap cars get and so they are not quite as strong and can not take the knock for very long causing engine failure.
I beleive the non-turbo models are absolutley fine.
Non Turbo models and any STi with PPP kits (fitted from delivery milegae) or 330s variant arent affected. Some STi's give out error code PO244, which is overboosting, but this is only on standard maps, and not PPP Ecus.
So if you have a 330s dont worry, if you have an STi.. be careful. Infamous video of a customer of ours ragging his new STi on YouTube (0-60 starts at full throttle etc), came in a week later with 7k on the clock, requiring engine rebuild, new crank, rods and pistons, engine casing, as number 4 piston was melted.
And it isnt the only STi to have it happen to...
No difficulties with WRX/WRXs's yet.