That sounds about right for the only negatives with the G56 pipes.
Only thing I would add, and it is related to your #2 is..... watch out in wet weather. The traction you had running a stock exhaust on wet pavement is also no longer there.....
And the bump in power is why i installed this tire.
Symmetrical tread pattern and softer compounds. Blizzak.
2019 M3W Sold and is now in Las Vegas enjoying the showgirls :-)