Regarding the price, it looks like 30% more for the base CS, without optional CCB (~9000€), DKG (~3000€), etc.
Noise: better than Competition, especially inside, but not loud/good enough from outside.
Lap time difference: M2C had the advantage of low temperature, while M2CS had better tirs (Cup2 vs PSS).
I would say, with identical temperatures and tires, the 2 seconds will stay the same.
Conclusion:A good step in the right direction, but not big enough to clearly differentiate it from he competition.
And it recommends the manual transmission, to enjoy it while it lasts. DKG is quicker though.