Here is what I am told by Weatherford BMW in Berkeley CA: yes, the original Bridgestone Ecopia 20" 175/55 R20 rear tires are out of stock nationwide, and at at least a month away from returning. However, as of this Monday BMW released a bulletin that Bridgestone is releasing a replacement tire in the meantime. I was unable to find out the difference between the original and the replacement, and frankly the whole thing sounds a bit dodgy. However, again according to this BMW dealer, the replacement cannot be mixed on the same axel with the original, so if you have a fatal puncture you must replace both rear tires with this replacement, and in order to sooth the blow Bridgestone will pick up the tab on the second tire. Sounds fair. I have a pair on order, being shipped up from SoCal, should be installed by the end of the week, for which I have a written estimate for $236.00 to "Replace right left rear tire per bulletin". Plus courtesy new & improved engine mounting bolt and software update.