The visual updates are minor, to say the least. 
I´m wondering if the 2017 actually produces more power than the 2016 model.
Officially the 2016 produces 367 HP, but it seems very hard to find a car with less than 390 HP.
Most dynoed stock cars (no remapping, no cat fiddling) produce 400+ HP.
It´s obviously done that way for marketing reasons - not to cannibalize on more expensive models in the Audi program.
So perhaps they simply gave the engine a very slight tune-up to make sure the 2017 delivers 400+ HP.

As for 0-100 times, forget about the official 4.3 (2016) and 4.1 secs respectively.
V-box tests show that most 2016 models do it in 3.9-4.0 secs. Some even as low as 3.6.
The new 400 HP TTRS with 80 kg less is even more ridiculously fast.

@noone : Yes, it´s mindblowing that a "regular" hatchback can outperform a Ferrari 360 by appr 1 sec from 0-100.
As for driving pleasure and handling it gets more subjective :)