do you have to take the front bumper off if you install a new grill? thanks.

 

If you're talking about a grill like this from street scenes then no.

 

No

 

thanks. i am thinking about getting the b-cool billet from courtesy parts. would i have to take off the original grill? how about the street scenes grill?

 

The street scene grille like on the above picture fits over the stock grill.
I was able to install it without lifting the car or even using a screwdriver.

You can reach from the open hood all the places where you need to put the clips on for the street scene grille (if you don't have superthick and short arms that is).
The only thing that took a while is to make it fit on top. I had to do a bit of squeezing and bending on the sides... And if you are not careful you can scratch the paint area around your stock grille.

Probably if you lift the car, unscrew the bottom, you can fit it much more easily and you can probably put the clips on better, or more to the outside (left and right).

Don't know about other grilles.