Jonathan,
The spoiler in the first picture was the spoiler on the early aerokit equiped cars commonly called a "taco spoiler" due to when the spoiler is viewed from the side it looks like a taco shell.
My 996 looks exactly like the car in the first picture, only I have GT3 style wheels.
If you look at this thread from Rennlist, you'll see someone doing exactly what you want to do.
First post, exterior mods - Rennlist Discussion Forums
Good luck with finding and building your 996. They are a great car!
Rick