All of these winglets and lips and other pieces of equipment are just waiting to be ripped off as soon as wheel-to-wheel contact occurs. These rubber-band bumper attachments are great for street cars and time trialers, as they are easy to install.
They would get quickly ripped off during even glancing contact. This is why you commonly see flush quarter-turn fasteners or recessed latches securing body components on most standard race cars.
Then again, when you look at things like the DTM series, there are canards and winglets and aero bits everywhere. They generally get broken off and go flying everywhere, all the time. But those cars also cost about 4x what a time trial 135i costs, so, there’s that…
For those who listen to the Slip Angle podcast, you may recall a fierce debate about whether or not the transponder being in the front or the back of the car would improve lap times (hint – it doesn't).