it was -25 in calgary this morning, may pajero started but it was a fight. i dont have a block heater(yet) but i do have an oil pan heater.
but without pluging in i have started in the morning at -12 with only a bit of effort. i may suggest that you check your oil. I know im going to catch it for saying this but i did notice that my cold starts where easier after i changed the oil. Also I went from 5w30 dino to 5w30 synthetic, syntestic seems flows better in the cold and helps with cold starting. seems to be working for me so far.
but i do plan on installing a block heater and getting a timer for it.