[wylde1]

You're probably going to need some of those vertical supports to hold the shape on the front of the fascia. the top will sag down a bit without the grill in there to support it. Unless you reinforce the top section with something so it holds shape.

another issue you might come across is that the grill itself is not smooth. It's got a texture to it, and you might be able to see the difference if you sand the bondo smooth. I would recommend putting a thin coat of the filler on the whole grill and sanding it. That way everything has the same texture, and it will look seamless.