It's my o/s front wing that I need to replace.
It's mostly just bolts. Most of which will break. Generic instructions:
1) Jack the car up, remove the wheel and wheel-arch liner.
2) Attempt to undo the nuts/bolts (bottom of wing, inside wing, front of wing).
3) Curse as bottom-of-wing and front-of-wing bolts shear.
4) Drill out bottom-of-wing bolt.
5) Remove wing, recover sponges, disconnect repeaters.
6) Put wing/bumper interface plate into a vice and drill out the bolts.
7) Install new wing and pull repeater light cables through the holes.
8) Put interface plate in place and run stainless bolts/nuts through it and wings.
9) Install lower bolts.
10) Spend about 2 hours aligning the wing and getting the shut-lines right.
11) Tighten everything up.
It's nowhere near that easy, but that's the idea.