Is it at all possible to add the carbon fiber options to the order on my standard S? If not, can I special order these pieces direct from Tesla to be installed by myself or my body shop?
Nope. That's all that's left from the performance only perks, you could ask someone to sell the spoiler though.
But you might be able to get a spoiler from someone who is receiving their spoiler after delivery of their car. It sounds like some may be changing thir minds about the spoiler.
TMC has an area for want ads.
And I'm sure eventually there will be aftermarket spoilers available.
Or paint a banana black and glue it on.
Or simply have carbon fibre film applied to the areas you want. The spoiler you may need to get from someone who has changed their mind.