These could be promising. They're made of polypropelene, which the MAXSA tracks are (and I believe they have a good reputation). Polypropelene is what most car plastics - especially bumper protectors on every modern vehicle out there - are made of. They are flexible, have good rebound (little chance of plastic deformation), and decent strength. The replaceable studs are interesting. I wonder, if they supply you with extras, or give you the option to purpose them, have they designed the product with the assumption that it won't fail like cheaper alternative could, and thus, there's a need for replacing wear surfaces?
Also, not sure if these are the legit thing... but it seems you can get MaxTrax for relatively
cheap on ebay. The shipping price is a tad crazy, but I've had luck taking that down a notch when buying Australian Subaru parts (large, plastic wheel well protectors and fender flares), so its worth inquiring.