Many tires get louder as they age. Some tires are just noisy right from the start. But remember, the Crossfire has some of the widest rear tires in the industry, so a little more road noise is to be expected.
If you're looking at a 2007 model with its original tires, I'd guess that's where most of the noise came from.
I'm on my 4th. set of different brand tires, and every single set had their own distinct sound.
I've owned a couple dozen sports cars over the years, and with out a doubt the Crossfire "coupe" has been one the most comfortable and quiet of them all.