Pretty much just pull them off. They are held on by four studs that go into plastic/metal clips.
The clips will come off with the wing, so you'll need to replace them. The upper three are plastic with a metal ring in the base that locks onto the stud on the wing. It was something of a PITA to remove them, since the metal ring didn't want to let go of the stud.
The bottom one is the same plastic retainer used by the roundels - it's a tight fit, so you'll have to pull with steady, even force straight out from the car. I've pulled several off without breaking anything, but, of course, the potential is there...
So, for each side you need
51 13 1 870 459, 3 ea. (retaining clip)
51 13 1 904 479, 4 ea. (foam gasket)
51 14 1 902 279, 1 ea. (plastic clip)
and for both sides, order one of 51 13 1 906 969, which is the foam rubber gasket that goes along the inside edge where the wing rests on the body. It's one long piece, you just cut it to fit.
