2025G0540i wroteI had this exact part in my cart before finding this thread. Honestly not sure why it doesn’t come black from factory. I have a white g05 so the diffuser on mine comes white as well but that black makes for a perfect contrast.There are none but you can see from the diffuser you bought it has a handful of screws on the bottom and 2 rivets. The top part and sides attach with little tabs. Just remove all the screws and drill out the 2 rivets. Use a drill bit about the size of the rivet center pin. The top and side tabs pull straight out without much of a fuss. Install in reverse order. You really don't need those 2 rivets to hold it on so I'm not sure why BMW designed it with those. But if you do replace them you'll need 2 rivets you can get from your dealer or any rivet will work that fits that size. And of course you'll need a rivet gun as well.
I’ll drop pics once installed.