Block heater installation?

[Johnomx3]

Hay there, i searched it on the forum and couldnt find the info i needed. i contacted Mazda and asked for a price on a block heater for my 92 mx3 sohc and the price was outstanding. Anyways i gotta drive my mx all winter and in northern ontario (-40 degree nights) and lower, can really cause rough to no starts lol. Anyways i was wondering if anyone knows of any decent block heaters say Canadian Tire may have that will work and fit in our car? Also someone told me about a iron heater i think where a big magnet attaches to the side of the block and heats up when plugged in, even that would be one hell of a better idea. Anyways please reply and thanks.