Going against my usual opinion here, but I think the black on the back looks kind of good on that color car. What doesn't look right is that the (rear) corners are still red. That doesn't match. Can you do them the same? I think it would look good on that color, and it needs to match across the back. Now that you have the rear bumper, you have an excuse to really supercharge that 4.6L.
Other:
Yeah, lose the window stickers, that's not really good for shows, IMO, if that's your goal, from what I see at car shows. I think they bring down what is otherwise a very, very sharp looking car.
Also, get some subdued exhaust tips. The stock exits on an SC are just visible in the corners and is sharp. Makes people wonder, but big tips poking out cheapen the car.
I'm not a fan of neon's at all, but have you considered dressing the engine with some chrome and putting in some strobes to show it off? Just 1 or 2 under the hood, in back or by the radiator will show off an engine well and it is very tasteful.
Overall, it's still a sharp looking car. You can improve it a lot by removing rather than adding at this point. Cheaper and easier that way too. Just commenting due to your post, constructive only.