Didn't happen today specifically, but my car does have a few G-spec mods - mainly from when I first bought it.
The rear parcel shelf, 1 side near the hinge/clips has a crack in it, did it when carrying tyres in the boot one time.
Left rear number plate light, I cracked one of the side clips that holds it in place. Happened when changing out the bulb to LED.
My rear muffler. I've been too complacent to get an aftermarket exhaust; but I've unbolted the stock one from the midpipe. So it's hanging/swinging freely from the exhaust hangers - from the rear axle to the tip the whole rear muffler/exhaust assembly is just sitting there for show.
K&N high flow panel filter
CP-E Austenite 304 stainless steel dual muffler catback
Evo X OEM bypass valve
Injen upper intercooler pipe