You definately want a gun thats winter friendly, if you're putting a high FPS AEG + winter do not mix well because you will crack your mechbox. Battery charge degrades a lot faster in the cold so get a high mAh battery.
Think in terms of reducing stress on your mechbox, M100 springs, proper lube, silent headset/dampening devices.
YANHCHAN'S AIRSMITHING: AEG repair/Tune up/Upgrades V2/V3 mechboxes, rewiring/reconnecting.
Ask not what your country can do for you; ask what you can do for your country ~John F. Kennedy