We are replacing a set on a 97 Marathon XL40 that is being purchased by the founder of CruiseAir. The parts are $1,112.00 from Prevost, and we are having ABC bus do the instal for $1,000 for all 8. The air bags on this coach look much better than the ones Tom pulled. I replaced all 8 on my 92 about 2 years ago, and the old ones looked great. I think that the environment the coach is in has a large impact on how the bags/rubber hold up. My guess is that cold weather is a big contributor to the rubber deteriorating.