I am in the market to replace my Ecopias. I went to Discount Tire and inquired about the Energy Saver AS and the tech told me he would go with the new Michelin Defender tire. He said they are almost as efficient as the energy savers and will last much longer and provide much better traction. How many mpgs can I expect to lose? Any suggestions? Also my Ecopias EP20 have only 23,000 on them. I have rotated every 5,000 and they are at 4/32. They also are wearing on the outer edges? Is this normal?