Which companies have used core competencies to improve their production?

The most obvious answer I can give you is Wal-Mart versus Target stores.  Wal-Mart thrives on its "low cost" angle.  However, Target thrives on its "better quality" product.  Target does not want to be in the same "category" as Wal-Mart.  They want to be compared with higher end stores like department stores.  Target also appeals to a more affluent shopper.  If you have shopped there you will notice their aisles are wider, you don't wait long at the cash register, and the return policies are much stricter than Wal-Mart's.  On the other hand, Wal-Mart has cheaper everything, they even guarantee the lowest price to anyone that brings in a flyer from another store.  However, for store brand quality, Target usually rates higher.  Let's face it, they make good stuff.  See attached a link to core competency definitions.