You need to re-adjust your boost controller,as in the winter time the cold air makes your turbo's build more boost,remember colder air is more denser The same thing happened to me few weeks ago as while i was driving to town and suddenly the car felt insanely fast and after few punches i realized that i was also boosting 1.5 bar . Since than i have turned the boost ( MBC) to 1.2 bar,don't wanna upgrade to single yet.
My car used to pop off hoses all the time, when I first went BPU, a couple of years ago. Just tighten them down really good and you should be just fine. Pushing 1.5 bar on stock twins when it is really cold out is not that unusual. Even with my Profec-B turned off I would hit 1.2-1.3 bar on a cold day. With it set to high boost I could hit 1.7 bar easily in the cold.
Your car is just runing rough because you fouled out your plugs from blowing off your intercooler pipe. Buy some new plugs or just clean the old ones really well. You'll be just fine. Don't run that much boost all the time though, it will quickly wear out # 2 turbo if you do it for a long time, about 20,000 miles. I wouldn't go over 1.2 bar unless you are really racing some one.