First off, congrats on the purchase! I haven't driven a '15 yet but I did get to ride in one, it certainly handles better for sure...handles like it should instead of forcing the owner to spend a couple grand to make the car handle like it should from the factory.
As far as the power, you're one of the first I've heard say it feels faster, most people I've talked to said it feels sluggish and he powerband feels really jerky. Of course every car is different and everyone has a different opinion on how they like the powerband to be delivered so that needs to be taken into account as well.
Lastly, I wouldn't hold your breath on the ringland issues being fixed, it's still the same powerplant and the dynos I've seen on the stock tune don't look very good to say the least. If it were me I'd still be slapping a custom tune on it as soon as I could afford it!
But good stuff dude, glad you're happy!