Hi michelino
The lower grille is actually stock as part of the vehicle
In Aus, the liberty is sold in two grades:
Non-sport - 2.5 NA, 3.6R
Sports - 2.5 NA, 2.5 T
The sports grade comes with the lower grille that you've pointed out, and the similar foglight surrounds (like the one in your avatar).
The non-sports grade has the same front buymper/bar that you've got on your lib.
Note the front bar/bumpers are different between the two grades, so I suspect it wont be as easy to 'plug n play' - ie. you would need to buy the whole front bar/bumper of the sports model and replace your existing front bar.