The Eureka K2 XT is a great tent for cold weather. Just make sure you leave at least one vent open at the top or you will be moist in the morning. I've used it several times in cold weather this year and it's performed very well. We had a problem after 2 days of rain and then a 10 degree night. My girlfriend zipped the vent closed because she was cold, not knowing that the condensation would make us colder.
This doesn't really answer your question, but I thought you'd like to have a bit more confidence in your tent. I was a little unhappy with the 12 lbs, but if you can lug it, it is definitely worth it.