I would even though I enjoy driving my GT more than any of my other modern performance cars. The question posed is to trade "even up" and I'm assuming the '16 GT, with it's more limited production, considerably improved performance, and kick ass great look, will in short time be the more valuable of the two. So it seems a no brainier to me(I excel at no brainers).
If the above proves out I can sell the '16 and buy the '06 pocketing the difference.
If the above proves out I can sell the '16 and buy the '06 pocketing the difference.