I have a 2005 C320 Sport sedan with 28,000kms or about 18,000miles on it. I had it in for it's B service and they told me the brakes have about 15% left and the waring light should come on soon (10%). The car is starting to feel like a tank to stop and the discs are visably VERY worn. I'm wondering if this is normal for the car? I live in the wide open praries, so no hills and I'm not an overly aggressive driver. Also the 145/40/17 Continental Sports on the back are finished after maybe 15,000 kms of use (I have winters too). I have never done a burn-out in the car, or fishtailed it out around corners, and I don't speed around town. Is all this wear premature, or is this usual for a Mercedes (I'm a first time owner)? Any feedback would be appreciated. I haven't been on this site before simply because the car has been entirely problem free. I also own a 2005 Cadillac CTS which I can't say the same about, and I'm a very well known/long time member of their forums.

Thanks!