So, welcome to the forum as this looks like your first post.
You are asking for some of the hardest original parts to find for the G8.
Hood scoops. I found a pair, new, a year and a half ago but never seen anymore come up. There are some used ones that show up periodically but may need some repair. There have been a few choices popping up on eBay that you may want to try. If you search the forum, there have been a few posts lately with links to hood scoops.
Spoiler - Probably not going to find an original. I bought one that was crack, took it to the body shop and they did a great job repairing and installing it. Again, best bet is to search eBay or choose an aftermarket spoiler of your choice.
Days parts yard is always rolling ss, g8, Caprice, Camaro, Corvette across their website and Facebook page. If you don't see it quickly on their website you might just give them a call. They make comments quite often that if you don't see it get a hold of them because they might just have what you need. Good luck.