I recently purchased a 2014 Mustang GT. I was looking at my Roush exhaust when I noticed this large hole in some plastic cover.

Any ideas what this is and how much it'll be to get fixed?

 

Call me Captain Obvious, but it appears as if that happens to be directly under the trunk. You know, right where the spare tire well is.....

Either that or you have some special drug smuggling container.

As far as cost, well it will cost as much as someone charges you. Or you can patch it yourself or get a replacement from a local junkyard.

 

That looks like the cover over the evap equipment. And I'd say that the previous owner backed into a culvert or curb or something to do that kind of damage to it. It sits too high to have been damaged just driving on the street.