INFO: Over the past few weeks, I noticed the left rear tire was slowly losing air. Recently, while I was out of town for 4 days, the tire lost 14psi. Took this 2015 CPO SLK to a nearby trusted indy to locate the leak, and he showed me that the OEM tire had once been plugged to fix a leak, and it was now the source of the leak. The leaking plug was also near the outer tread edge, so not wise to repair it. The car has just over 16K miles, and both rear tires were showing wear bars. Replaced the rear OEM Continentals (ContiSportContact) with the Michelin Pilot Sport A/S 3+. I've had good experience with Michelin Pilot Sports over the years; hopefully my good luck will hold. Normally, I would have replaced all 4 tires; however, the front Contis still have approx 60% tread left. Total cost for the new rear tires w/hazard warranty was $495.