Touring Equipment

I dont look at limit or extreme temperatures. Figure out what the minimum temp you will be having is like and look for a sleeping bag with a comfort zone close to it. You can always open it up if youre hot but you sure as hell cant make it warmer when youre feeling cold.
A bit late to the party with this but a sleeping bag liner can make a difference. I've got a silk one that was about a tenner. I pack it down in my sleeping bag when out and about so you don't notice any additional bulk. Makes it warmer in the bag and easier to wash as you wash the liner and not the whole bag.