Over the years, I have flown in cold temps (14f or -10c), or colder, in the clouds and as long as engine and guages are properly preheated , the airplane runs very well. I always keep some power to the engine to keep the cabin from getting too cold on descent, I have heard about shock cooling, but believe that with a normally aspirated engine, that this is an old wives tale. I am not sure how well a plastic airplane would do, but I know that most auto plastics, including fibreglass cars handle cold well. That being said, ice chunks will typically crack plastic parts if they are struck with any force. Winter flying is great, airplane and engine performance is better then than any other time, but crosswinds may tend to be much higher.
Fly safe, fly often. Tony Wright