Seems a bit warmer here today. It was -1 when I left this morning as opposed to -4 yesterday morning. Have seen it as low as -7 in the last week though
Did you get a video of it yet? Mine used to make a kind griding noise when cold but it was due to the y-pipe rubbing against something.
I never noticed any power loss when I cut mine out. I will be cutting out the silencer on my greddy exhaust when I get chance aswell