I broke down and waited a half hour on the phone to talk with a very nice fellow at Air Rite. Basically, the 88113's have a "jounce bump stop" on the inside of the round springy thing, so that if for some reason the spring loses air it won't smash down and get ruined. Both 88113 and 57113 have same weight capabillity (5000# each) and same mounting stuff, and both would work on the toyhouses. No difference in the ride, sway, bottoming out, or "squat." He did say that if you have a broken air line and the 57113 spring gets destroyed, there is a lifetime guarantee and the company would replace it.
