If you have a '04 like your sig states, you have a Flat Tire Monitor, which depends on ABS sensors that measure the relative speeds of 4 wheels. If you have checked all your tire pressures and reinitialized the system properly and still get a warning, perhaps something is wrong with the ABS sensors.

I think I might be trying the Pirelli Neros next. They weren't available in the P235/50R18 size, or else I would have gotten them. I have a new set of Kumho Ecsta SPTs, which were rated highly for summer tires, and cost a lot less. The ride also got better, despite the upsize and summer rubber. I thought it was a win-win situation: less cost, summer performance, better ride. Then I tested out the handling and pushed the X3 through some corners. Bad news: the tires totally ruined the at-the-limit handling. Now I'm wary of trying out passenger tires on a SAV :eek: