To start off i live in Buffalo, NY and its the begining of the long winter.
everytime i go to start the car in the morning the exhaust rattles like crazy(same noise as when you hit a pothole or bump) untill the engine reaches about 180, only does this on cold startup
i think the noise is comming from the muffler
any ideas?

 

Maybe it's a clamp that is loosening up somewhere. It will rattle when cold, but when the pipes heat up and expand, it fills the clamp just enough to not rattle.

Check and tighten some clamps, that's my suggestion.

 

I had the same problem, all you have to do is have whoever installed your exaust re weld it. Mine rattled very bad but after they welded it again the problem ceased.If you still have your stock exaust im sure it will apply to that also