Story in Autocar this week. Seems that if you bought an impreza recently it may be up to 2 years old as no new ones have been brought into UK in past 2 years!
This happens alot. Like my focus is a 05 plate but they stopped making my shape of focus in January 2004 . Just keep them an don't register them so that they can get a better price.
I once got sent an investors pack for PSA - i.e Peugeot Citroen, and in as late as 2004, Pug 405 and Citroen ZXs were being produced, albeit in small quantities!