I think I know what car you are talking about. The blue one? Chrome supercharger on it maybe?There was a guy on auto trader selling a g8 that was supposed to be some kind of auto show demo. vehicle. Definitely not a color I had seen before. I looked to see if it was still posted for sale but nope. I thought he said there where only a few done in this color to. Forget what they called the color.
The firehawk doesn't really count in my book 'cause it's a third party modifying a factory built car.