Leave it black, it'll look fine. I had a CF hood on my old black supra, and it looked fine, I'm sure that CF will look fine on your bumper. You can always have the shop spray the bumper, or the bottom part of the bumper, black first and see how it looks before you totally repaint your car. Just my $.02
The Do-luck replica looks really good. Especially with the carbon fiber being wrapped around the edges! I wish this replica had come out 4 years ago, instead I paid $4,000 (no C/F) to have it shipped from Japan back in the day. This definitely is worth the $1500 bucks if the fitment is decent. Let us know how the fitment turns out.
This is my old Do-luck kit.... See how I sprayed the black around the edges to make it stand out a bit. I wish this would have been C/F instead of having it painted black. Go for it dude! Sorry guys about the pic size.