Will My Headers be useless?

[Grip72]

I was planning on storing my car for the winter and doing some body/engine/interior mods on it. I really want to get headers but i just read a post on how they tend to crack when it's cold out. I live in Northern BC Canada and it tends to get pretty chilli up here, meaning it got as cold as -41 Degrees Celcius last winter (that was the coldest day). And i will probably have to drive it in winter sometime soon, so is it pointless to get headers on my car? Also, will putting headers on my car have a great effect performance-wise? (i will have a Ractive CAI soon and hopefully a new muffler)