I wouldn't worry about the Airex core. I've had my boat for 27 years and haven't had any problems at all. This is a very well made boat. The interior of the boat does not sweat as some do and the boat is warm in the fall and cool in the summer. When I had the boat made 1n 1981 they emphasized the Airex core as a selling point. If you want to know more about the boat check out this brochure.
http://www.msogphotosite.com/MSOG/pd...cross28bro.pdf
Don Smith
Rochester NY