They do make the plates but i am not sure where you get them. I have on that was in my old cavalier but my cousin gave it to me when i bought the car from him. I would check places like parts express.
metra has a kit so does best kits and AI. You can use a heat gun and a 2x4 to melt (soften it up not set on fire or put a hole in) and push the duct back so you can use a flat or "flatter" front panel. I have seen anywhere between flush to extended out by 2" on s-10's