The G81 is the first M3 Touring BMW has built, and the easiest car in the range to misunderstand when buying parts. At the front it is an M3, at the back an estate, and both are true at once.
In practice: bonnet, widened front wings, bumper and grille surround are the same parts as a G80's. Rear doors, rear quarters, roof rails, the tailgate with its separately opening window and the rear lights all come from the ordinary G21 Touring.
So most of our G81 stock is really G21 stock: doors, mirrors, bonnets, aprons. The genuine M front-end parts are scarce, because few of these were built and fewer still get broken.
The G81 was only ever made as a Competition with xDrive. There is no manual and no rear-drive version, which at least makes driveline parts easier to search for.