I got 30K out of my stock Dunlops and replaced them with Kumho's. Everybody complains about tires splitting, cracking, and bubbling. One thing you can do to prevent this is regulary check the air pressure of your tires. It's amazing the difference you will see in handling and gas mileage with the proper air pressure. Low tire air pressure combined with hard cornering puts extra stress on tires. I'm not saying this is everyone's problem, but it is definitely something to check into.