Chances are the "New" battery in your car isn't that old, since the original batterys seem to have an "average" life span of around 4 years.
Lots of performance minded Crossfire owners actually look for a "smaller" or "lighter" battery to replace the original just to make the Crossfire less "nose heavy". (improves handling).
As long as the battery you now have starts the car everytime, and holds a good charge, I wouldn't change it.