-10 this morning, I don't run the trek top all winter, I just put it on a couple of weeks ago. I can't say i have had any problems in the cold but it is definitly tougher to put it on when it is cold. I wouldn't change it for anything, well maybe topless !

 

I run the factory soft top all year long up here in Canada. -30 and the jeep is not really hot but its still comfortable. You don't need to wear cloves and a touque in it. Go for it, put the trek top on...... I've been wanting to put the top down since it got around 0c (32 f) out.

 

If you have somewhere to store the hardtop, then go for it. I am going to either build a winch system, or buy on so I can store the hardtop all summer (the whole 3 weeks of it). We have around the same type of weather as you do right now, and I want the top off.
Like others have said in response to your post, just turn the heater on if it gets too cold.