Storing brushless e-revo in the garage

It should be fine, but if you can, I would try to find some extra space inside for it. Under the bed, hidden in a closet, something. Just to be on the safe side.

Like I said, it should be fine. Cold won't damage any of the electronic components, and it shouldn't damage a the magnets on the motor. But the E-Revo is an investment, and its always important to protect your investments.