I test drove the track edition a while back but my 2012 Z was love at first sight, given the fact that I already had a 300zx, 350z, 09 370z which I traded for the 2012Z (impulse buy) Great deal was not upside down.
Anyways, I can tell you that the Genesis track edition interior is awesome blows the Z interior away. But I still felt that the Z was more aggressive and felt more manly. LOL.
Here is my advice, since you just got your Genesis a while back and only 10k on it I would just keep it. I am not a fan of going back to an 09 especially the Z that year was not a good year for the Z. If you do decide I would try to go for a 10 or 11. I am willing to bet right now if you would go to your local Nissan dealer and just be straight out and tell them pay off my car and I will jump in your Z I bet they can work something out. In the end it will be up to you this is just my 2 cents.