Shouldn't break that easily. I know it's not flexible, quite brittle actually, just make sure you don't twist it though and you should be fine.

I ended up with two screws in the wheel well, one above the other, because if you just use one screw for this section then the lip will flex up/down a bit as the single screw will act as a pivot point. I received those little black caps that cover the screw so that can't be seen easily.

For the two screws I used on the front I just put them through the back corners (when facing the car front on) of the 'flap' that sits in the grill section, one for each corner. I did this because of the way the stock bumper is shaped - the screws have to be as far back as is feasible so that the screw will go through and into the bumper on a decent angle (you'll know what I mean).
I also sprayed these screws back so that they wouldn't stand out.

Good luck with it man