Jim
The Maggiolina Extreme is a nice tent - I use one myself. The difference between the Extreme and other Maggiolinas is the construction of the top. Since the Extreme has a built-in rack system it requires that we stiffen the roof, which is done by using a double shell in parts of the rear of the shell that creates a space that is filled with injected structural foam. In order to support roof loads the lift mechanism is re-inforced. These two variances make the Extreme heavier than a standard Maggiolina by about 15 pounds. Weight is critical in RTTs, so the Extreme is only made in small size.
If weight were not an issue, a tent could be built like an ice-breaker. But we keep the weight of our heaviest tents (large Maggiolinas) to less than 155 lbs. in keeping with roof rack loading limits imposed by OEMs and the largest suppliers of racks - Thule and Yakima.
The composite upper shell of a Maggiolina is designed to flex under stress. This is accomplished, in part, by the fiberglass fabrics selected, the lay-up process, and the resins employed. About the only damage we see in these tents is when someone forgets the tent is up there, and drives into a parking garage or under an overhanging tree limb. Fortunately the upper shell can easily be repaired by a boat repair shop using standard marine fiberglass repair techniques (West Systems publishes a series of very good guides, as well).
In short, the single real advantage in choosing an Extreme over other Maggiolinas is the ability to carry modest loads on the roof rack. All the Maggiolinas have the same materials and capabilities (except as noted above) and performance in extremes of weather. I have used my Maggiolina down to 15 or 20 degrees F. Other users report use in temps below zero. The materials used operate very well in extremes of temperature, and, with the addition a of a winter hood and appropriate bedding, will serve you well in Fairbanks - even in winter.
PS: The internal volume of a tent is very important in cold weather camping. A low ceiling and minimum interior volume will retain the sleeper's body heat much better than a large, high top tent. This is the same idea that is employed in the small mountain tents used by climbers and arctic travelers. The addition of a 12V under mattress heater further insures a warm night's sleep.
