Anyone know of other unique modifications like the Audi R8 roofbox or Reliant Robin stabilisers?

I was wondering if anyone knew of any other quirky or unique car modifications. The only ones I can remember off the top of my head are:

-Audi R8 roofbox
-Koenigsegg Agera roofbox
-Reliant Robin stabilisers
-Lotus Esprit submarine kit (doesn’t exist anymore)
-Peugeot 205 huge wing
-Various police sirens

Surely there much be a load more, especially with a next-gen Forza game.