anyone know anything about superchargers??

I have an 07 cobalt ss sc, when i bought the car i asked if it had a block heater (like i do any other car) the sales guy said yes of course. Later i find out there is no block heater so i go back and tell them, they tell me that my car doesnt need a block heater and it will be just fine. This morning i get up it is about -22C outside and my car doesnt start. (i live in canada) So i call the dealership again and talk to another guy, he informs me NOT to get a block heater because it will wreck the supercharger. Is this true? He said something about how the block heater causes the oil to get warm and that is what will do the damage.

He instructed me to pick up a battery blanket and put that on it.

So now im talking to my friend who's taking some mechanic classes or something and i tell him and he says that they're pissing around with me; and that a block heater will not do anything to the supercharger.
Does anyone have any advice? should i or should i not put a block heater in my car!!!
Imo i'd think it would be better instead of just having a warm battery... isnt it hard on everything to start really cold? It gets to -40C where i live...