Here is a post I found quite informative. It is by a pretty well known tuner named Clark Turner. I just thought I would re-post it over here for people to check out:
Another reason I will never invest in another Subaru again unless the car has been rebuilt by an independent owner. When you have a manufacturer purposely putting junk in a 30k+ car, not just junk that will effect the handling, junk that will cause catastrophic failure they have failed. I could not imagine paying 35k for a car that needs an aftermarket tune just to run right and new pistons in a year with no mods and normal driving and then just to add insult to injury (if you are under warranty which you would not be with the aftermarket tune), Subaru then fixing everything with the same junk so it will happen again. I will never talk bad about Ford again LOL! Completely outrageous