Well... long story I might say. This happend to me as well.
When the weather was cold the steering did crumble when at full lock. Also, the steering pump was making this whining noise and getting louder.
So I took the car to my trusty mechanic. With his help and reading all the forum information I could find I ended up changing the whole system.
Apparently, the earlier Breras had the steering system designed with a red/pinkish steering fluid in mind. But that one get's too viscous at lower temperatures and they changed it with a green fluid. But they forgot to mention that everything had changed in order to change the fluid. So I changed the fluid and the reservoir (because it was spilling everything out). Then the pump blew up and changed that. After that we just lifted the car on an elevator and the steering rack blew on one side with all the fluid spilling out of control.
Crap...

After a few hundred euros (AR did not consider this a warranty issue) and a few weeks waiting for parts I practically changed the entire system.
I can't say this is the same issue you all have.
BUT after changing everything the steering works perfect... No more noises whatsoever, no more tire scrape, no more whining and the steering is precise and smooth.
PS: Also, you should know I have the 19" TI wheels on.