I just found this cool manual on Google books while searching for "snow trac." It's an old book (1962) but covers everything from airplanes, helicopters, buildings, ice roads to everything else about Antarctic logistics...including Snow Tracs and Tuckers. Starting on page 388, there's a good discussion of the ST-2 with the Porsche engine, even some pics of one stuck in a crevasse. There's a list of recommendations for design changes and it looks like maybe Aktiv was listening to at least some of those. Neat stuff! My apologies if this was posted elsewhere.