The eBay item number is 220800059946, listed as NEW REAR AIR RIDE SUSPENSION SPRINGS BAGS BMW X5 E53. You should be able to search eBay Motors for it. Seller is listed as arnott_air_suspension from Cape Canaveral, FL. You could also probably contact them at Arnott, Inc., 1-800-251-8993, or on web at arnottairsuspension.com. My guess is that the price will be different for your model and due to them being the front air springs, etc. Still maybe a bargain!