My '02 didn't have a grill when I bought it used. It had been cut out. It is part of the bumper. I would have replaced it if it didn't mean buying a whole new bumper.

 

The grill fits on several plastic pins that come out from the back of the bumper. Then it is secured with metal tabs that grip the plastic pins. They're really easy to brake off so chances are if you had to replace the whole bumper it was b/c all the pins were broken off. However, you can take a flathead and pry the metal tab off. If you jack the car up and look behind it, you can see all of them.

 

the grill is probably there to protect your radiator from being hit by whatever you may encounter on the hwy... so unless u have a fmic then i'd leave it there

 

I'd cut it out if I had an intercooler, wait, I already did that.