Yer Ive done my liberty one but it was pretty easy. I had a look at my mates 06 WRX and a bit of cutting would need to be done as well as a lot of bog/fibreglass. Not sure if there is an aftermarket grill that already looks like this tho. If you got me another grille, I'd have a crack at it.

Ill try find some pics of mine

EDIT - heres some of the grill bogged up and unpainted.

Used to look like this


Now like this