Will a used Subaru from 2006 still have a warranty?

I am looking for a replacement car and have a budget. I have seen a Subaru Legacy that I like from what seems a reputable used car seller. However, I am a little petrified of the known Subaru cylinder...

Is it worth remapping the ECU in my car?

Is it worth the cost of a remapping of the cars ECU on my BMW X1 2.0d?