I've owned two C7 Z06's. There is no comparison between the Mustang GT and the Z06. The Z06's were without a doubt the best bang for the buck cars I've ever owned.
I had the same issue with mine not starting and throwing all kinds of codes with around 300 miles on it. The dealer replaced the gateway module and it's been fine ever since. I now have about 3,400 miles on the odometer.
I have the Project-6GR 10-spoke wheels in gloss black on my car. I believe I have the 19x10's on the front and 19x12's on the rear, but I could be wrong. My car is in storage, so I can't look at it right now. The folks at Project-6GR were great to deal with. I'm don't know how to post pictures...
Faster or not, I really don't care. The front of the Charger looks like another boring electric car and the fake engine noise is, well fake. Kind of like wearing a pair of corduroys without making a "swishing" noise when you walk. I'll take my Mustang GT anytime over the Charger.