Ok I'll be that guy. Put off the new car purchase until you pay off your debt and car notes. Then set aside some cash for a rainy day fund. Once you've got that taken care of, go nuts. It's not the fun thing to do, but it's the right thing to do. You're in a great position to get your finances in order. You may not get this chance again for a long time especially if you start playing with super cars. I put off my turbo build for years while I put all my bonuses and overtime earnings towards paying everything I could off. Now any extra cash I have can go towards my hobby without any guilt or risk. It's a good feeling. Sure cars are never a smart investment, but if you've taken care of everything else then at least you're still in good shape financially.
That being said, my vote is for the C7. 700 hp is easily achievable without breaking the bank. There's a shop already making over 1000 whp on the stock block (of course they don't expect it to last long). Good luck my friend and congrats on the promotion