Damn, sorry for your loss man. I wish you a speedy recovery. I lost my mustang last month as well but will hopefully be back in the saddle soon. I hope that your insurance makes you whole again. Dont get a Camaro lol.
Remove the liner under the decklid and check for yourself for bolts/hardware. I thought mine had holes but I came to realize that it did not and that the spoiler was just held on with double side tape. 2016 GT
Exhaust leak maybe? I'd look for carbon buildup around the connection points of the exhaust. Might not be too obvious now since you have such low miles.
From one Joel to another, get the GT. You get used to the power so no worries in killing yourself unless you do something really retarded. If you can swing it, get the GT. If you cant, save up until you can. Its worth the difference.