Does anyone else also find their brakes substantially grabbier the first few times they're applied from a cold start?

 

yes. I noticed that too. I just thought it was because of the new braking system and that I was used to my 07

 

The brake dust gets damp and will cause this, go to auto store and buy a spray can of Brake kleen and spray it around the caliper so the black crap runs off then drive.

 

Yes....it is not unusual for new brakes to do that. It should reduce/elminate over time

 

Does anybody notice a growling noise from the rear brakes in wet conditions>?

 

Its probably either the traction control or ABS doing its job.

 

I know the difference between brake noise and traction control and ABS.
Let me rephrase my question and describe it.
After going through a car wash or driving through puddles or after it's rained is when it happens.
The rear brakes make a groaning noise when coming to a normal stop on dry pavement.