It was minus ten here just last week, in fact the morning I took the new truck in for under coating and rustproofing. Thought I'd try the remote starter, she fired right up, block heater wasn't plugged in either. :E On a side note: that remote starter will really spoil ya, by the time I went out and got into my truck the driver's side seat and the steering wheel were roasty toasty!
I never plugged in my '06. NEVER had an issue with that truck not starting, don't expect to have an issue with this one either. Last winter was one of the worst winters for us here in the upper midwest and it worked out ok for me.
I'm not saying you shouldn't use your block heater, I'm just saying you probably don't need to use your block heater. To each his own, YMMV. My truck is also equipped with tip start.
Dan